Three English clubs and both Celtic and Rangers are hoping to secure places in the last 16 of the Europa League this week, while former European Cup winners Ajax and Inter Milan are bidding to qualify in adversity, for different reasons.
AFP Sport picks five last-32, second-leg games to watch:
Manchester United v Club Brugge
Ole Gunnar Solskjaer's side hold the upper hand following last week's 1-1 draw in Belgium, but all is not lost for the visitors given the problems goalscorer Emmanuel Dennis repeatedly caused the United defence.
United's latest financial results revealed revenues fell by almost 12 percent in the six months to December, underlining the club's need for a return to Champions League football next season.
The arrival of Bruno Fernandes could provide just the spark required. The Portugal international scored his first United goal in a 3-0 win over Watford at the weekend. He also impressed in a brief cameo in the first leg.
Ajax v Getafe
After their memorable run to the Champions League semi-finals last year, Ajax are in serious danger of making a limp exit from Europe this season as they welcome Getafe to Amsterdam trailing 2-0 from the first leg.
Only five members of the team that started last season's second-leg loss to Tottenham Hotspur in the Champions League were in the team for the defeat in the Madrid suburbs last week. One of those, midfielder Hakim Ziyech, has already agreed a transfer to Chelsea.
Also beaten in the Dutch league by Heracles at the weekend, Erik ten Hag's team are in the process of being broken up and overturning such a deficit against a Getafe side currently sitting fifth in La Liga is a big ask.
In any case, the match may not even be the priority this week for Ajax, as they face AZ Alkmaar in a top-of-the-table clash in the Eredivisie on Sunday.
Porto v Bayer Leverkusen
A precious away goal by the Colombian Luis Diaz kept alive Porto's hopes of progressing to the last 16 as they lost 2-1 to Bayer Leverkusen in Germany in the first leg last week.
The Portuguese side have otherwise been in good form recently and will be hopeful of turning the tie around back at the Estadio do Dragao, especially as the Bundesliga outfit have lost top scorer Kevin Volland to an ankle injury which could rule him out for the rest of the season.
The tie is a meeting of two former winners of the competition or its forerunner, the UEFA Cup -- Leverkusen won it in 1988, while Porto lifted the trophy under Jose Mourinho in 2003 and again under Andre Villas-Boas in 2011. Both sides started the season in the Champions League, but Porto went out to Krasnodar in the third qualifying round and Leverkusen finished behind Juventus and Atletico Madrid in a difficult group.
Inter Milan v Ludogorets
The rising panic over coronavirus is overshadowing Inter's simple looking second-leg clash with Ludogorets, who have little chance at the San Siro following their 2-0 defeat in Razgrad, as Italy grapples with an outbreak that has left 10 dead and over 300 people infected.
The chaos caused to the country's sporting calendar has hit Inter hard, with the weekend's postponed Serie A match against Sampdoria set to be played at the end of the season and Thursday's meeting to be played in front of empty stands.
The lack of home support is another problem for Antonio Conte's side as they try to bounce back from a defeat at Lazio 10 days ago that has left them six points off the pace at home.
Conte still has to deal with the absence of goalkeeper Samir Handanovic, out since the start of the month with a little finger fracture.
Arsenal v Olympiakos
Mikel Arteta's Arsenal host Olympiakos looking to extend a 10-match unbeaten run which has seen them unexpectedly launch bids to reach next season's Champions League on two fronts.
The Gunners started the year languishing 12th in the Premier League, 11 points off the top four.
But they now sit just four points adrift of fifth-placed Manchester United, with a top-five finish potentially enough to qualify for the Champions League after Manchester City were handed a two-year ban by UEFA for financial fair-play breaches.
A 1-0 victory over Olympiakos in Greece has also put last season's Europa League runners-up in pole position to reach the last 16 as they bid for a first European trophy since lifting the Cup Winners' Cup in 1994.