Sanchez, who has scored 20 goals this campaign, was left to sit alongside second-top scorer Theo Walcott, who has 15, in a game that is pivotal to both teams' hopes of Champions League qualification.
Wenger, whose future is in doubt as his contract is up at the end of the season, opted for Olivier Giroud and Danny Welbeck to lead the attack.
"I play with Giroud and Welbeck up front because we decided to have some fight in there and be a bit more direct," explained Wenger.
Arsenal, who are also without ill playmaker Mesut Ozil, occupied the fourth and last Champions League spot ahead of kick-off, a point ahead of fifth-place Liverpool.
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