Joel Campbell believes Arsenal's strength in depth will enable them to cope with the absences of Santi Cazorla and Alexis Sanchez in the crunch Champions League trip to Olympiacos on Wednesday night (9 December). The Gunners need to triumph by two clear goals – or one if they score three or more – to make it to the final 16 of the tournament.

Manager Arsene Wenger previously revealed that both Sanchez and Cazorla will miss the game, with the Spanish midfielder being ruled out for up to four months after undergoing surgery necessitated by a rupture to the external knee ligament. Francis Coquelin, Mikel Arteta, Jack Wilshere, Danny Welbeck and Tomas Rosicky also remain in the treatment room, but Campbell says the Gunners squad can cope with these issues.

"The truth is that we have had bad luck with injuries. There have been injuries for players who are very important to us but we are a big club and we have great players [to cope with the situation]," Campbell said to IBTimes UK after the 3-1 victory over Sunderland. "We have to step up and move forward."

Campbell himself has seized the opportunity to break into Wenger's plans, first replacing Aaron Ramsey and Alex Oxlade-Chamberlain on the right flank and now doing the same from the left to fill the gap left by Sanchez.

"It's not just me, the whole team are leading the way, it's the only way to go," Campbell said after scoring his second goal of the campaign in the Sunderland win. "All of the players are giving their best and it's paying off on the field.

"I can play in three positions: left, right and in the middle of the attack. Wherever the boss plays me I try to do my best."

Having spent the 2013-2014 season on loan at the Greek outfit Campbell knows the challenge posed by Olympiacos will be tough. However, he feels the win over Sunderland will help the team arrive to the game mentally ready in what he labels the most important match of the season so far.

"[The win over Sunderland] was a good result for the team. We got the result and that's what we wanted. Now we have to prepare mentally and physically for Wednesday's game because it will be very difficult," he said. "We already played against Olympiacos at Emirates Stadium. They are a great team, a great rival and especially because they play at home. In the Pireo [Karaiskakis Stadium] it is very difficult to get points but it is the last game of the group stage and we will give our best.

"It is the most important game of the season so far. It will be a cup final and we have to win to continue in the Champions League."