The UEFA Champions League knock-out phase enters its most critical point this week, with the first of the Last 16 second legs taking place.
Big games such as these are often regarded as matches for heroes, a time for the top players to shine through and lead their clubs on toward glory.
For Paris Saint Germain and Valencia, they will both be hoping that the biggest key men in the game play for their own club—but both will also have to do without some of their best players.
Here is a run-down of the key individuals for both sides, with the first leg ending 2-1 to PSG, who also have home advantage for this second leg.
The Ligue 1 league leaders will be missing several stellar names from their lineup, but without doubt, the biggest miss is top scorer and star striker, Zlatan Ibrahimovic.
The Swedish forward was sent off late in the first leg so misses out through suspension.
That puts plenty of emphasis on Ezequiel Lavezzi to come up with the goods in the final third for PSG.
Lavezzi scored the opening goal of the first leg and has hit four goals in four starts during this season's Champions League, double the amount that Zlatan has managed to date. His pace, ability to run with the ball at his feet and his terrific work ethic will be big pluses for PSG, who will be able to counter attack at speed with Lavezzi leading the line.
Another player missing for the home side through suspension will be Marco Verratti, so his defensive midfield partner Blaise Matuidi will see responsibility fall on his shoulders for protecting the back line.
With PSG already ahead on aggregate, and having two away goals to their name, there is no need for the French side to roar out of the traps in full attack mode. They can afford to be patient, play the ball well and wait for Valencia to commit themselves.
When Los Che eventually do that, Matuidi will be key in ensuring that the defence remains steadfast and in control, by not allowing Valencia's midfield runners to have an impact from deep or overloading in central areas of attack from the second line.
For PSG's third player to have a big impact, they will look for somebody to attack the channels with pace and power—someone who can create a goal that will give them great breathing distance in the tie.
Step forward Lucas Moura.
The Brazilian impressed in the first leg with his desire to get at the Valencia back line, and he can certainly do the same again at home.
For Valencia, though, one more goal scored against them doesn't essentially change their job on the night—they have to score twice. They will always be more reluctant to commit too many men forward early on, in the knowledge that Lucas Moura is ready to pounce into the spaces they leave.
First and foremost, while Valencia cannot over-commit, they do need goals.
Winning 1-0 will see the Spanish team eliminated on away goals, so two strikes in Paris is the bare minimum requirement.
Therefore the burden of responsibility falls most heavily on Roberto Soldado, who now really has to step up and show the quality levels he believes he has.
His 13 league goals this season is respectable, if not overly impressive, but he has also hit four goals in six games in the Champions League. That is both more pertinent and more impressive, and he will almost certainly have to add to that tally on Wednesday.
Behind him, in the line of attacking midfielders, Ever Banega has the mental ability and level of technical quality to control the match if his fellow midfielders can keep giving him the ball, especially with PSG's Verratti out of contention.
Banega can dictate the rhythm of Valencia's game, and he can continually provide the passes for others to have chances on goal. Expect him to drop deeper if he doesn't receive plenty of possessions early on, but he will be central to Valencia's chances of success either way.
Finally, whilst goals are important, it's no use scoring twice if they also concede two more.
Who will be the key player in the second leg?
While PSG can be gotten at, they were also far superior to Valencia in the first leg, and it is inconceivable that at some point during the second leg, goalkeeper Vicente Guaita will not be severely tested.
He certainly could have done better at times in the first leg, being beaten rather too easily by a couple of chances, and he will need to be at the top of his game to keep out the likes of Lavezzi, possibly Kevin Gameiro, and also Jeremy Menez.
Any or all of these players could have a significant impact on the second leg as a whole, and don't be surprised to see one of these six have the decisive moment of the match—whether that be a well-taken goal, a defence-splitting pass or a super-reflex save.
The odds are on PSG progressing, but Valencia have the quality players to turn it around if they are on their game and get a little luck.