Europa League highlights: Arsenal, Atletico cruise (VIDEOS)
Arsenal manager Arsene Wenger says his side have done "half a job" after a "spectacular" first-half performance saw the Gunners take control of their Europa League quarter-final by demolishing CSKA Moscow in the first leg.
Alexandre Lacazette and Aaron Ramsey scored two goals each as the Gunners hit four in 26 minutes before half-time.
Arsenal were unable to add to their tally in the second half but they will head to Russia's capital for the second leg next Thursday with a commanding lead.
"We have to be realistic. We have to do the job over there, go and try to win the game, that's the best way," said Wenger.
Ramsey's side-foot finish set Arsenal on their way.
Aleksandr Golovin levelled with a sublime free-kick before France striker Lacazette, who has recovered from a knee injury, made it 2-1 with a penalty after Mesut Ozil was fouled by Georgi Schennikov.
Ramsey produced a brilliant third with an instinctive volleyed flick, with Lacazette adding a fourth after being picked out by the outstanding Ozil.
"We have done half of a job," added Wenger. "There was a good pace in the first half, the two teams gave everything, which is why is was such a spectacular first half."