Arsenal and Bayer Leverkusen will have to pull off two of the biggest shocks in UEFA Champions League history if they are to overturn the deficits from the first legs of their Round-of-16 ties. And they must do it against two giants of the European game.

The Gunners need to become the first team in Champions League history to overcome a 4-0 first-leg defeat in order to progress beyond AC Milan. Meanwhile Bayer Leverkusen, who beat Bayern Munich in the Bundesliga at the weekend, have to defeat Barcelona by at least two clear goals at the Camp Nou to advance to the next round.

Lyon’s and Zenit St Petersburg’s progress is far from certain either, with both sides taking slender one-goal advantages into their second legs with APOEL Nicosia and Benfica respectively.

This week’s fixtures
Tuesday 6 March
Benfica-Zenit St Petersburg (first leg 2-3)
Arsenal-AC Milan (0-4)

Wednesday 7 March
Barcelona-Bayer Leverkusen (3-1)
APOEL Nicosia-Lyon (0-1)

Match of the day
Benfica-Zenit St Petersburg, Estadio da Luz, Lisbon, 20.45 CET

Benfica, who will be playing in their 50th Champions League match, have never lost at home to Russian opponents, with a record of two wins and two draws from four previous encounters. The Portuguese side also recovered from a similar 3-2 first-leg defeat by Napoli in the 2008/09 UEFA Europa League to win the return fixture 2-0. But while they have scored at least one goal in each of their last 19 European home games, there are two factors that may work against them this time around. 

The first is the absence of influential Argentinian playmaker Pablo Aimar through suspension. The second, a 3-2 home defeat by arch-rivals Porto at the weekend, on the day the club celebrated its 108th anniversary. Zenit, meanwhile, are unbeaten in their last six Champions League outings, and have just returned fresh from the long Russian winter break. Their first game back was a 2-2 draw with title rivals CSKA Moscow, which helped them hold their place at the top of the Russian league table.

The other matches
Arsenal-AC Milan
Arsenal returned to form at the weekend with a 2-1 win away at Liverpool, but they will need to be at their very best if they are to have any hope of turning around their 4-0 first-leg defeat by AC Milan. The Gunners’ defence will also have to contend with an in-form Zlatan Ibrahimovic, who hit a brilliant 14-minute hat-trick against Palermo on Saturday. Robin van Persie and Co have lost just one of their last 42 home games in the Champions League, but victory alone will not suffice this time around. A monumental effort will be needed to see off the Rossoneri, whose two previous visits to the Emirates Stadium ended in goalless draws.

APOEL Nicosia-Lyon
Despite dominating the first leg, Lyon, who are in the knockout stages for the ninth consecutive season, only managed to convert a single chance. The omens look good for Les Gones, however, as they have progressed 14 times out of 16 after winning the first leg at home. APOEL, the first Cypriot side ever to have reached the Round of 16, have already reversed a similar scoreline this season. Having lost the first leg of their Champions League play-off against Wisla Krakow, APOEL won the return fixture 3-1 to secure their place in the group phase. All told, they have prevailed twice and been knocked out twice after losing first legs 1-0 away from home in this competition. The Cypriots also have a strong home record, having lost just one of their ten home games in the Champions League this season.

Barcelona-Bayer Leverkusen
Barcelona took a big step towards the next round with a 2-0 away win in the first leg, and they go into the return fixture looking to extend their 14-match unbeaten streak in Europe. The reigning champions will be without their Chilean forward Alexis Sanchez, however, after he picked up an injury on Saturday that will rule him out for the next two weeks. Bayer Leverkusen, meanwhile, have the odds stacked firmly against them, but they are unlikely to leave the Camp Nou without a fight. Robin Dutt’s side have not won any of their last 11 away fixtures (8 defeats, three draws) but their 2-0 league win over Bayern Munich at the weekend will no doubt give them hope of securing an unlikely turnaround.

Player to watch
If Arsenal are to have any chance of clawing back the four-goal deficit from their first leg against AC Milan, they will almost certainly need a big performance from Robin van Persie. The 28-year-old Dutchman is in the form of his life and already has 35 goals this season, including 25 in 27 Premier League appearances and four the Champions League. “I’m a true Gunner. I love this club and that's no secret,” said the forward, who found the net twice against Liverpool on Saturday.

The stat
26 out of 52
– Barcelona have won 26 of their 52 matches in the Champions League knockout stages. Only Manchester United have a slightly better record, with 27 victories from their 56 knockout encounters.

What they said
“They [APOEL] will need to show more endeavour than they did in the first leg, which could give us opportunities on the break. We’ll need to be mentally strong, because they’ll have the whole city behind them,” Remi Garde, Lyon coach.

Have your say
Can Arsenal and Bayer Leverkusen recover from their first-leg defeats and record unlikely wins?