Arsenal will embark on what seems to be 'mission impossible' when they travel to 37-game unbeaten Barcelona on Wednesday looking to overcome a 2-0 first-leg deficit in the last-16 stage of the Champions League.

A double from Lionel Messi has placed the Spanish giants in firm control of the tie as Luis Enrique looks to lead the reigning champions into the final eight of the competition for the ninth consecutive season.

Barcelona

No team has successfully defended the Champions League in the modern era, although AC Milan did win back-to-back European Cups in 1989 and 1990. In recent memory, no side has been better placed to achieve that feat than Barcelona, who are on the verge of the quarter-finals following an impressive victory in London last month.

Enrique's side were far from their best in the English capital, but a second-half double from Messi ensured that they would take a two-goal lead into the return. The Catalan outfit have actually reached at least the semi-finals of this competition in seven of the last eight seasons and have won the trophy in four of the last 10 campaigns.

Arsenal need to score at least twice at Camp Nou to stand a chance of staying in the tie, but only Bayern Munich (3-0) have beaten Barcelona in Spain by at least two clear goals in their last 12 Champions League appearances. Add in the fact that the Spanish giants are chasing their 10th straight home win in this competition makes it even more unlikely that the visitors will be able to upset the odds this week.

Alongside Real Madrid, Barcelona were one of just two teams to go through the group stages unbeaten and they comfortably finished top of Group E. The Catalan outfit have actually progressed on 35 of the 37 occasions where they won the first leg away from home in a European tie, and they have only lost two of their 30 home games against English opposition in UEFA competition.

There is also the small matter of Barcelona's 37-game unbeaten run in all competitions, which stretches back to the start of October. Since then, they have won the Club World Cup, reached the Copa del Rey final and opened up an eight-point lead at the top of the La Liga table.

Fifteen goals have been registered in their last three matches and they are currently on an eight-game winning run in all competitions. The incredible trio of Messi, Luis Suarez and Neymar already have 103 goals between them this season and Arsenal, realistically, will have to keep a clean sheet on Wednesday to stand a chance of progressing. Nothing in football is impossible, but it is very, very difficult to see a route back for the Gunners.

Recent form: WWWWDW
Recent form (all competitions): WWWWWW

Arsenal

Arsenal, alongside Real Madrid, are one of just two teams to have reached the knockout round of the Champions League every season since the new format came into being in the 2003-04 season. While that record is impressive, the Gunners have been eliminated in the round of 16 in each of their last five campaigns.

In terms of their progression this season, Wenger's side managed to finish second in Group F behind Bayern Munich, despite losing three of their six group matches. They lost three of their first four matches in the section, but advanced courtesy of a 3-0 victory at Olympiacos on matchday six, which gave them a superior head-to-head record over the Greek team.

Not since 2010 have Arsenal reached the quarter-finals, and their ability at this stage of the competition has been rightly called into question due to the fact that they have lost the home leg of their last-16 ties in each of the last three seasons. The Gunners have also never overturned a home first-leg deficit in a European competition.

Thierry Henry scored the only goal of the match as Arsenal won 1-0 at Real Madrid at this stage of the 2005-06 season, but they have lost on eight of their last 13 trips to Spain in European competition. What's more, they have lost both of their last two-legged affairs with Barcelona in the Champions League.

Wenger's side will also enter this match off the back of a 2-1 defeat at home to Watford in the quarter-finals of the FA Cup at the weekend. They have only won one of their last seven games in all competitions and currently sit 11 points off the pace in the Premier League table.

Realistically, Arsenal's season could be over this weekend if they were to exit to Barcelona and then lose at Everton in the league on Saturday afternoon. The pressure is firmly on Wenger once again and it will be fascinating to see whether he chooses to rest players ahead of the trip to Goodison Park.

Recent form: LWLWWL
Recent form (all competitions): LLLDWL

Team News

Barcelona will be without Gerard Pique through suspension, which is expected to open up a spot in central defence for Jeremy Mathieu, who has seen plenty of football this season.

Elsewhere, Enrique has no fresh injury concerns and the XI almost picks itself. Marc-Andre ter Stegen will replace Claudio Bravo between the sticks, while it will be the 'MSN' in the final third of the field.

As for Arsenal, they are expected to be boosted by the return of Laurent Koscielny, who took part in a training session on Tuesday morning as he recovers from a calf problem.

The Frenchman's expected return might well see Per Mertesacker drop to the bench and Gabriel Paulista, who has experience of Camp Nou following his time with Villarreal, selected in the XI.

Wenger must also choose between Danny Welbeck, Theo Walcott and Joel Campbell for a place in the final third alongside Olivier Giroud, Mesut Ozil and former Barcelona attacker Alexis Sanchez. Petr Cech, Santi Cazorla, Jack Wilshere, Alex Oxlade-Chamberlain and Aaron Ramsey, meanwhile, all remain out of action.

Barcelona possible starting lineup:
Ter Stegen; Alves, Mathieu, Mascherano, Alba; Busquets, Rakitic, Iniesta; Neymar, Suarez, Messi

Arsenal possible starting lineup:
Ospina; Bellerin, Gabriel, Koscielny, Monreal; Coquelin, Elneny; Welbeck, Ozil, Sanchez; Giroud

Head To Head

Barcelona have come out on top in both of their previous two-legged European affairs with Arsenal.

The last time that the two sides met in the Champions League was during the 2010-11 season, when the Gunners lost 4-3 on aggregate - including a 3-1 defeat at Camp Nou.

The previous season, Messi hit all four goals as Barcelona recorded a 4-1 victory at home to Arsenal in the quarter-finals of the competition. Barcelona also beat the Gunners 2-1 in the 2006 European Cup final in Paris.

We say: Barcelona 3-1 Arsenal

Arsenal will fancy their chances of scoring on the night due to the absence of Pique, but it is very difficult to see the Gunners stopping Barcelona down the other end. The visitors will be forced to come out and play, which will play into the hands of the reigning champions. We are predicting a comfortable progression for Barcelona.