Per Mertesacker believes Arsenal must put their upcoming Champions League clash with Bayern Munich to one side as they prepare to take on Blackburn in the FA Cup fifth round on Saturday.
The Gunners host the Championship side just four days ahead of welcoming Bayern to the Emirates Stadium on Tuesday.
While it is easy to start dreaming of a victory against the German side - who are currently running away with the Bundesliga - Mertesacker says the north London club must focus on booking their place in the FA Cup quarter-finals first.
"We still have an important cup game on Saturday - we absolutely want to advance in the FA Cup, that is why the preparations for Bayern are not that intense yet,'' Mertesacker said.
"However, beginning on Sunday the preparations for Tuesday's match will be extreme. Bayern are doing superb this year and that is a big challenge for us, but we are looking forward to both legs.''
With the Bayern game looming, Arsenal manager Arsene Wenger has indicated he could rotate his squad for the FA Cup tie, looking to protect the fitness of several key players.
Captain Thomas Vermaelen has missed the last two matches because of an ankle problem, requiring him to receive injections. The Belgium international, though, has hinted that he should be fit in time for Tuesday.
"At the moment I feel great, I trained all week, so hopefully I will be back really quickly," he said during a Q&A with fans on Arsenal's official Twitter account on Thursday.
Wenger later revealed that Vermaelen was "looking quite good" and could even be included in the squad for this weekend.
However, the Gunners boss said midfielder Jack Wilshere was still being closely monitored after coming off against Sunderland on Saturday with a dead leg.
"He is having tests today and tomorrow," Wenger told the club's official website. "Jack is looking better. He is still a doubt for Saturday. He's got a kick on the thigh.''
Centre-back Laurent Koscielny also remains a doubt with the calf injury that saw him limp out of the warm-up at Sunderland, after originally picking up the problem while away on international duty with France. Full-back Carl Jenkinson is suspended for the cup tie after his red card at the Stadium of Light.
With Kieran Gibbs still sidelined by a thigh problem and Andre Santos having joined Gremio on loan, Wenger's defensive options are limited, so 20-year-old Ignasi Miquel looks set to be involved against Blackburn.
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Information from the Press Association was used in this report