Mikel Arteta saw Arsenal scrape through to the Europa League quarter-finals and warned the demise of Tottenham shows there are no formalities in knockout football.
Arsenal took charge of their last-16 tie with Olympiacos in Greece last week by opening up a 3-1 advantage, but a 1-0 defeat at Emirates Stadium on Thursday made for a rockier than expected route through to the final eight.
Gunners manager Arteta said Arsenal were "nowhere near" the required level and did not hide behind the fact his team avoided the same fate as their north London rivals, with Tottenham given a shock 3-0 hiding by Dinamo Zagreb to perish 3-2 on aggregate.
Speaking about Tottenham's miserable fate in the competition, Arteta – whose side lost three consecutive home matches in European competition for the first time in their history – said: "It shows as well the level of opposition, that people take for granted that you play against an opponent and you will go through, because of the name of the club that they represent.
"It is not like that, every team in Europe is difficult to beat."
Arteta only found solace in the fact Arsenal – who reached the quarter-finals of the competition for the fourth time in their last five campaigns – avoided Europa League elimination.
"If I have to evaluate the performance with what we've done today, with the ball in particular, then it's nowhere near the standards we have set for ourselves," Arteta said.
"We made it really difficult because we didn't have any stability when you give the amount of balls away that we have in the game.
"When that happens, you don't have the control to manage the tie in the way that we should have done and that's related to the amount of chances we missed again."
4/5 - Arsenal have made it to the quarter-finals for the fourth time in their last five Europa League/UEFA Cup campaigns (knocked out at Last 32 stage last season), after failing to reach that stage in each of their first five attempts. Relief. #UEL— OptaJoe (@OptaJoe) March 18, 2021
Tricky opposition will await Arsenal in the quarter-finals, with this competition particularly important given that winning it represents their only realistic path into next season's Champions League.
Premier League rivals Manchester United, Roma, Villarreal and Ajax are among the sides to have made the last eight.
Arsenal's dressing room was a quiet place after the game, goalkeeper Bernd Leno said.
Leno told Arsenal Media: "Everybody knows that it was not a good performance from us. We cannot change it anymore but the positive thing is that it was a warning. We need to be 100 per cent every game. If we play like today then we won't reach anything this season.
"This is probably the closest way to go to the Champions League and also to win a big European trophy so we need to step up."
Arteta, meanwhile, said Arsenal would not rush to pull Bukayo Saka out of the England squad for the World Cup qualifying games at the end of the month.
The young winger missed Thursday's fixture with a muscle injury but may have a chance of facing West Ham on Sunday, and if he misses out then Arsenal will consult with the England camp.