These next few weeks will go a long way toward shaping how successful some top European sides' seasons can truly be.
The Champions League round-of-16 second legs, kicking off Tuesday, will determine how we view the likes of Borussia Dortmund, Real Madrid, Juventus and Liverpool's campaigns.
On Thursday, the Europa League steps in, pitting clubs like Arsenal, Napoli and Inter Milan against tough opponents that present a serious threat to their hopes of silverware.
It's time to take stock of these clubs ahead of what promises to be a pivotal set of fixtures.
The European Club Rankings is a list of the continent's top teams in order of form and performance at this stage of the season.
You can read the previous set of rankings here.
20. Benfica (New!)
Sevilla drop out this week after suffering yet another loss, so in their place come Benfica.
Their recent strong form has seen them wrest top spot in the Primeira Liga off FC Porto—thanks in part to the Eagles' victory over the Dragons this weekend—and Europa League success is still on the cards.
19. FC Porto (-5)
For the first time in months, it is not FC Porto's name at the top of the Primeira Liga, but Benfica's.
They've won just three of their last six fixtures, losing two of them, which is a far cry from their end-of-2018 form, where they beat just about every team they encountered.
They're going to have to conjure a big performance to get past Roma in the Champions League this week.
Their fall of five places is harsh, but it reflects their rough patch of form in comparison to other clubs in the rankings.
18. AC Milan (+1)
It was a pretty solid week for Milan, who kept two more clean sheets en route to a 0-0 draw away to Lazio and a 1-0 win at home to Sassuolo.
The draw was in the first leg of the Coppa Italia semi-finals, meaning a home win in the second leg seals a path to the final. Weirdly, though, the second leg isn't until late April!
17. Lille (+1)
Much is often made of Lille's attacking talent and goalscoring power, but recently it has been their defensive solidity that's seen them through games.
This weekend's 1-0 win over Dijon was their third clean sheet-victory in their last five Ligue 1 matches, and they've conceded just once in that span.
16. Arsenal (+1)
Arsenal have peaked and troughed pretty violently this season, so when the team look good—like right now—the fans have learned to appreciate it while it lasts.
They destroyed AFC Bournemouth 5-1 in midweek then outplayed Tottenham Hotspur at Wembley Stadium on Saturday only to contrive not to win. The performance was encouraging, though.
15. Lyon (+1)
Lyon made light work of Toulouse at the weekend, winning 5-1 courtesy of goals from Memphis Depay, Bertrand Traore, Nabil Fekir and Moussa Dembele.
The XI fielded was full-strength bar one player (Lucas Tousart in for Houssem Aouar), so manager Bruno Genesio will be praying they can all stay fit now, therefore maximising his chances of causing an upset in Barcelona in the Champions League next week.
14. Ajax (+1)
A 3-0 away win over Feyenoord? That's one way to warm up for a pivotal Champions League clash, Ajax!
They played that match on February 27, giving them just shy of a full week to prepare for their second leg with Real Madrid at the Santiago Bernabeu.
They're trailing 2-1 from the first leg and need to score at least two away goals to progress, so that extra preparation time will have been welcomed with open arms.
13. Chelsea (Stay)
Chelsea's last seven days were very good. In fact, you'd be hard-pressed to argue against the notion that they were some of the best they've experienced in some time.
Taking Manchester City to penalties in the Carabao Cup final was followed by a 2-0 win over Tottenham in midweek then a 2-1 win over Fulham in a local derby on Sunday.
The latter performance was by far the worst of the three, but the points earned mean winning their game in hand will take them to fourth.
12. Tottenham Hotspur (-1)
It's a good job Tottenham spent the first half of February stacking up victories because they've been rotten since February 23.
Three games played and not a win in sight, and they were fortunate Pierre-Emerick Aubameyang's last-gasp missed penalty in the north London derby secured them a point.
Spurs boss Mauricio Pochettino will be feeling thankful his side hold a 3-0 aggregate lead over Borussia Dortmund heading into the second leg!
11. Napoli (+1)
Any lingering, faint hopes of a Serie A title race were smashed to pieces on Sunday as Napoli lost to Juventus. Expect manager Carlo Ancelotti to go all in on the Europa League from here in search for silverware.
10. Real Madrid (Stay)
League: 3rd | Copa del Rey: Out (Semi-final) | Champions League: Round of 16
Losing one Clasico is tough, losing two in the space of a week is horrid.
But losing both at home, with one knocking you out of the Copa del Rey and the other opening a 12-point gap between you and your great rival in La Liga? That's borderline unimaginable—or it was, until this month.
Real Madrid fans have been through that this week. Spare them a thought.
9. Borussia Dortmund (-3)
League: 1st | DFB-Pokal: Out (3rd round) | Champions League: Round of 16
BVB are in a tailspin. There's no two ways about it.
One win in seven has seen their lead at the top of the Bundesliga shrink quickly, and they must now attempt to overturn a three-goal deficit in the Champions League on the back of a loss to Augsburg.
8. Manchester United (Stay)
League: 4th | Carabao Cup: Out (3rd round) | FA Cup: Quarter-finals | Champions League: Round of 16
United haven't half struggled through their last two Premier League fixtures—3-1 and 3-2 victories over Crystal Palace and Southampton, respectively—but wins are wins.
The injury list manager Ole Gunnar Solskjaer is battling is almost beyond belief, but they'll have to summon something ahead of Wednesday's trip to Paris Saint-Germain if they're to turn over the 2-0 deficit.
7. Atletico Madrid (+2)
League: 2nd | Copa del Rey: Out (Round of 16) | Champions League: Round of 16
A quick-fire brace from Alvaro Morata, who has been brilliant since joining on loan in January, helped Atletico Madrid ease past Real Sociedad on Sunday.
The XI fielded was pretty close to full strength, so Diego Simeone will have been relieved the match was settled early (though Koke's red card just after an hour did force some dogged defending), allowing him to turn his gaze at least partially to Wednesday's colossal clash with Juventus earlier than expected.
6. Bayern Munich (+1)
League: 2nd | DFB-Pokal: Quarter-final | Champions League: Round of 16
Bayern Munich are on the surge—and Thiago Alcantara, for one, is pretty happy about it.
They're showing the sort of fight most thought had abandoned them this season, and their latest win, in conjunction with Borussia Dortmund's loss, means they sit second in the Bundesliga only due to goal difference now.
What a remarkable turnaround.
5. Juventus (Stay)
League: 1st | Coppa Italia: Out (Quarter-finals) | Champions League: Round of 16
Juventus' 2-1 win over Napoli on Sunday was fraught, dramatic and ill-disciplined but, on balance, deserved.
The result opened up a 16-point gap between the Old Lady and second place in Serie A, sticking a near-definitive fork in any "title race" for another year.
4. Liverpool (-1)
League: 2nd | Carabao Cup: Out (3rd round) | FA Cup: Out (3rd round) | Champions League: Round of 16
For the first time since December 7, Liverpool sit in a position other than first in the Premier League table when they have played the same number of matches as rivals Manchester City.
Four draws in their last six games has seen their lead shrink and disappear, with Manchester City leaping ahead of them this weekend.
The defence is still rock-solid, but the attack is misfiring badly. That will be of great concern to Jurgen Klopp, who must not only go to Munich soon and score to progress in the Champions League, but who will also know goal difference may prove a legitimate factor in the title race.
3. Paris Saint-Germain (+1)
League: 1st | Coupe de France: Quarter-finals | Coupe de la Ligue: Out (Quarter-finals) | Champions League: Round of 16
A late Kylian Mbappe goal secured PSG an eighth straight victory in all competitions on Saturday, but while that would be impressive for most clubs, the French champions consider it par for the course.
Instead, they'll be more pleased about their positive injury news heading into their round-of-16 second-leg clash with Manchester United.
Marco Verratti is back among the squad, Thomas Meunier played 90 minutes at the weekend and Edinson Cavani's involvement isn't completely out of the question, per ESPN FC's Jonathan Johnson.
2. Barcelona (Stay)
League: 1st | Copa del Rey: Final | Champions League: Round of 16
Top of the league? Check. Healthy gap to second? Check. Copa del Rey final berth secured? Check. Double Clasico victory in the space of a week? Check, check!
Things are rosy in Barcelona right now; getting the better of your rival not once, but twice, on their patch in the space of a week will do that for you.
We're now in a position where the minimum expected of Barca's season is two trophies (La Liga and Copa del Rey). That said, the fans might not be happy unless that becomes three and includes Europe's most prestigious club prize.
1. Manchester City (Stay)
League: 1st | Carabao Cup: Winners | FA Cup: Quarter-finals | Champions League: Round of 16
Manchester City's 1-0 win over AFC Bournemouth on Saturday took them top of the Premier League table.
They've chased Liverpool down over the course of three months, turning a seven-point deficit into a one-point lead.
The statistics behind City's win have caught the eye of many. They accrued 81 per cent of possession and didn't so much as allow the Cherries a corner—let alone a shot on goal!
Injuries continue to beset them—Kevin De Bruyne limped off at the Vitality Stadium, adding himself to a pile already including Fernandinho and Aymeric Laporte—but they continue to grind through it.
All statistics via WhoScored.com