7 Players to Watch on Day 4 of the 2014 World Cup
The 2014 World Cup has already provided several great matches, with Italy's 2-1 win over England in Manaus on Saturday the latest top-quality fixture in Brazil.
Attention will now turn to Sunday's games, with Switzerland and Ecuador opening the day in Group E.
After that, former world champions France open their campaign against Honduras in the same pool.
The final fixture of the day sees Argentina take on Bosnia and Herzegovina at the Estadio Maracana in Rio de Janeiro in the opening Group F encounter.
But who will be the players to watch on Day 4 of the World Cup? Here we provide six key men to look out for on Sunday.
Lionel Messi, Argentina
This World Cup would not be the same without Lionel Messi in an Argentina shirt.
The Barcelona star will be looking to make his mark on the tournament when his country takes on Bosnia and Herzegovina at Estadio Maracana on Sunday.
The 26-year-old will also be hoping for a World Cup improvement this year after his relatively disappointing campaign in South Africa four years ago.
Diego Maradona's team excited the crowds in 2010 but were completely overwhelmed 4-0 by a well-organised Germany at the quarter-final stage.
Messi made his World Cup debut in 2006 at the age of 18, becoming the youngest player to represent Argentina in the finals when he stepped off the bench against Serbia and Montenegro.
But the 2010 tournament was a great disappointment for Messi and Argentina, who had promised so much in the early stages of the competition.
Now, though, an older and wiser Messi will take centre-stage for Alejandro Sabella's team when they open their group stage against World Cup debutants Bosnia and Herzegovina.
However, as Barney Ronay of The Guardian noted, Messi must shrug off the ghost of Maradona to prove himself as a genuine legend for Argentina.
Messi has scored just one goal for Argentina at a World Cup finals, leaving some of the country's fans to question any comparison to Maradona, who almost single-handedly guided the country to glory in Mexico in 1986.
According to Argentina team-mate Lucas Biglia, Messi is ready for this World Cup, as Vivek Chaudhary of The Independent reported.
The Lazio star is quoted as saying:
He (Messi) is very relaxed and will handle all the expectations. This is a different Messi you will see, not like at other World Cups. This is a team that will play to his strengths and make him comfortable so that he can make the difference.
But the difference in role for Messi between club and country can be neatly summed up by the personnel behind him.
At Camp Nou, the Argentine has a glittering array of talent such as Andres Iniesta, Xavi and Sergio Busquets working midfield, while, at international level, the backing is more of a holding variety.
As a result, don't expect the usual fluid Messi to emerge against Bosnia and Herzegovina. Instead, we can expect a more counterattacking role in support of Angel Di Maria in a more creative role.
Whatever version of Messi is available on Sunday, though, it will be compulsive viewing.
Xherdan Shaqiri, Switzerland
Arguably, Xherdan Shaqiri is the best-known player in the Switzerland squad.
This summer could be a busy one for the Bayern Munich winger, who has also been linked with a move to Liverpool, as Colin Harvey of the Daily Star reported.
The 22-year-old is playing second fiddle to Netherlands international Arjen Robben at the Allianz Arena, but it would be foolish to consider him a "lesser" talent to his more illustrious club team-mate.
Shaqiri has a style of play which tends to see him dribble in-field from his role on the right flank, before unleashing a fierce strike.
It will come as no surprise if Swiss head coach Ottmar Hitzfeld relies heavily on his star throughout the tournament, where Shaqiri will be playing the lead role rather than waiting for his chance behind Robben.
As WhoScored.com noted, the Bayern player's real strengths come with his crossing, passing and dribbling, while his ability to maintain possession makes him an invaluable member of the Swiss team.
However, his defensive abilities are open to question with his focus squarely on an attacking role.
But Hitzfeld is under no illusion about the player's ability, as Jill Zimmerli of The Guardian noted. The Swiss head coach is quoted as saying:
Xherdan is always calm when he is in possession of the ball. No matter who he is playing against. He is never anxious and he almost always unlocks his potential. In addition, he has a great mentality and can adapt quickly.
Against Ecuador, Shaqiri will be a key factor in Switzerland getting off to a fast start.
Antonio Valencia, Ecuador
Antonio Valencia might have slipped from the radar with Manchester United, but a positive World Cup with Ecuador could be ideal to reignite his club career.
Incoming Old Trafford manager Louis van Gaal is likely to be among several interested parties watching the former Wigan Athletic man lead out his country against Switzerland.
The 28-year-old is one of only a few remaining members of the Ecuador squad which featured in the 2006 World Cup, where England ended their involvement at the last-16 stage.
That experience and his time at the top level of the Premier League level will be invaluable for the unfancied South American team.
Valencia will be the focal point for his team with his right-sided role against the Swiss, although a question mark can be placed over his discipline, as WhoScored.com highlighted.
It is the winger's fearsome acceleration which could prove to be a decisive factor for Ecuador head coach Reinaldo Rueda, although it remains to be seen how the additional burden of the captaincy weighs on Valencia's shoulders.
But the Ecuador boss is a fan of the United wide man, as BBC Sport's Tim Vickery reported. Rueda is quoted as saying:
He is well balanced mentally. He's down to earth and gets on well with those around him. His team-mates hold him in very high regard because of the way he is. He's very charismatic.
Valencia will work in tandem with Jefferson Montero on the opposite flank against Switzerland, as they attempt to provide the ammunition for striker Enner Valencia.
Blaise Matuidi, France
There are more high-profile names in the France squad than Blaise Matuidi, but few make a difference quite like the Paris Saint-Germain midfielder.
Alongside club-mate Yohan Cabaye and Juventus star Paul Pogba, Matuidi is the fulcrum for Didier Deschamps' team ahead of the game against Honduras on Sunday.
The 27-year-old is fiercely combative in the tackle but also has an eye for goal creation and, more recently, the occasional strike himself.
His acrobatic goal against the Netherlands in a March friendly will live long in the memories of France supporters, and he added two more in the drubbing of Jamaica in a World Cup warm-up match.
He epitomises the perfect all-rounder in the centre of the pitch and fits Deschamps' profile for a midfield general with ease, breaking up opposition attacks with some pinpoint tackling while providing the start of French forward thrusts.
Matuidi possesses impressive stamina throughout 90 minutes. That engine has seen him earn plaudits across European football, with Deschamps leading the way.
Deschamps is quoted as saying after Matuidi's goal against the Netherlands, per beIN Sports (via Goal.com's James Coveney): "He is so committed in everything he does. At one point when he went to the ground it gave me chills."
Maynor Figueroa, Honduras
Maynor Figueroa is no stranger to Premier League supporters after his impressive form at left-back for Hull City this season.
But be prepared to see him operating in a more central-defensive position when Honduras line up against France on Sunday.
Figueroa is expected to renew his partnership with experienced San Jose Earthquakes man Victor Bernardez at the heart of the Honduran defence.
The Hull defender, 31, is likely to be a busy figure for his country at the Estadio Beira-Rio in Porto Alegre, where Karim Benzema, Olivier Giroud and Mathieu Valbuena are set to spearhead Les Bleus' attack.
But Figueroa will be a difficult opponent in the Hondurans' defence, as Arsenal striker Giroud has already warned, according to the Hull Daily Mail's Philip Buckingham.
Giroud is quoted as saying:
It's true that I like the physical part of the game. I won't shy away from that.
I was able to confront myself with the tough defence from England and it's an asset for me to have this kind of opponents every weekend, and I hope to use it against Honduras because they will give everything.
I have already played against Maynor Figueroa. He's not an angel on the pitch, he's quite tough, but it's fine.
Sergio Aguero, Argentina
If you are a wanted man in the eyes of Lionel Messi, you are definitely a player to watch. And so it is with Argentina striker Sergio Aguero.
Barcelona star Messi has previously called on the Camp Nou hierarchy to make a move for the Manchester City forward, as Rik Sharma of the Daily Mail reported last month.
Aguero suffered an injury-hampered season at the Etihad Stadium last term, but his 17 goals in 23 Premier League appearances were a defining factor in City clinching the title on the last day with victory over West Ham United.
His finishing remains a key factor for both club and country, and his eye for a goal-scoring opportunity has made him a key figure at all levels.
The former Atletico Madrid forward has experienced the World Cup after being in the squad which played under Diego Maradona in South Africa four years ago, but he is now at the peak of his powers after hitting 75 goals in 122 matches for City.
And now the 26-year-old is set to make his own mark on the tournament after emerging from the shadow of Carlos Tevez with Argentina.
Aguero is expected to play in a fearsome three-man frontline against Bosnia and Herzegovina at the Maracana on Sunday, alongside Messi and Gonzalo Higuain.
But the weight of scoring will be taken off his shoulders in such a strong line-up, which will allow Aguero more freedom to roam and use his selfless nature to create as well as find the net himself.
In December, Aguero voiced his gratitude for the praise of City manager Manuel Pellegrini, who claimed the forward was at the same level as Messi and Cristiano Ronaldo, as the Daily Telegraph reported (h/t Christopher Devine of Goal.com).
Aguero was quoted as saying:
It's really high praise.
To be mentioned in the same breath as those two guys is great. It's an extra incentive for me to prove every time I play that I can be compared to those guys.
You're always very happy when you hear your manager speak highly of you, but now it’s down to me to back that up every time I go on to the pitch in every game.
Now the time has come for Aguero to prove himself on the biggest stage of all with his expectant nation.
Haris Medunjanin, Bosnia and Herzegovina
Manchester City striker Edin Dzeko is, by far, the most high-profile name in the Bosnia and Herzegovina squad, but it will be a lesser-known player who could prove to be a key factor against Argentina on Sunday.
Haris Medunjanin might not be the most famous footballer in the world, but his importance to head coach Safet Susic cannot be underestimated.
The 29-year-old, who plays for Gaziantepspor in the Turkish league, is an experienced player across Europe, with spells at AZ Alkmaar, Sparta Rotterdam, Real Valladolid and Maccabi Tel Aviv also on his footballing CV.
But Medunjanin is a stylish player and represents the sole defensive midfielder in the Bosnia and Herzegovina squad, and his role in front of the team's backline will be decisive if they are to surprise Argentina.
As Slaven Niksic noted in The Telegraph recently, Medunjanin may not have the speed and agility of other players, but it is his strength and passing ability which make him so vital to Susic's plans:
If you need goals there's Edin Dzeko. If you're looking for a quality attacking midfielder Miralem Pjanic will do just fine. If a solid goalkeeper is required Asmir Begovic is your man. These players are all synonyms for quality in their defined positions, not only for Bosnian football but on a global scale. But what about those unglamorous players who put in the hard graft and often don’t get the credit they deserve?
For Bosnia that man is Haris Medunjanin and coach Safet Susic simply adores him – for good reason.
But while the experienced midfielder is a robust character, he also provides an impetus for counterattacks, which could prove integral to any hopes Bosnia may have against the world stars of the South American side.
Against Argentina, where the likes of Lionel Messi and Sergio Aguero lie in wait, Medunjanin's defensive capability will be to the fore, but a solid start to the campaign can help his country in the remaining Group F fixtures against Iran and Nigeria.