Bernd Leno admits Arsenal are facing a "very difficult" challenge to salvage their season after suffering from "big problems" throughout much of the campaign.
The Gunners found themselves as low as 15th in the Premier League at Christmas after a dismal run of seven defeats and just one win in 10 top-flight games.
Arsenal's defence of the FA Cup also ended with a 1-0 defeat by Southampton in January, while they were knocked out of the Carabao Cup the previous month.
But Arsenal's league form has improved dramatically in 2021 and the mood at the Emirates was further boosted with a 2-1 victory over local rivals Tottenham on Sunday.
Leno is relieved the "bad atmosphere" has lifted from the dressing room, although he is unsure his side can make up the ground they have given up to finish in the top four.
"We were completely lacking the consistency," the Gunners goalkeeper told German outlet Kicker . "In [the] autumn, we had big problems, a bad atmosphere… and we turned the corner.
"Now we’re at least getting a taste of the Europa League again. [To qualify for the] Champions League will be very, very difficult."
Can Arsenal qualify for next season's Champions League? Have your say in the comments.
Arsenal take on Olympiacos in the second leg of their Europa League last-16 tie on Thursday. The north London club have a commanding 3-1 lead from the first leg and will be confident of progressing to the quarter-finals.
Things are less promising on the Premier League front, however, with Arsenal 10 points adrift of the Champions League spots with a game in hand on fourth-place Chelsea.
Leno hopes victory over Spurs will be the impetus for a winning run to lift the Gunners up the league table.
"Hopefully, it will increase the level of confidence of the team and the belief that we can play really well against any opponent, we can beat big teams as well and just maintain everybody together with a big belief," he said.
"We know we have to put four or five wins together in a row to give ourselves any chance of looking up in the table, but we are ready for a fight."
Sign up to the Mirror Football email here for the latest news and transfer gossip.
