Arsenal have been steadily improving under coach Mikel Arteta after a difficult start to the season, following on from last term's eighth-placed finish.
Leicester grew into the match after their laboured start and had several chances to get themselves back into the contest before half time, only to find Gunners keeper Ramsdale in inspired form. A seventh win in that unbeaten run of nine means Arsenal climbed above Leicester who drop to 10th, with their inconsistent form this term hurting them.
The visitors did not have to wait long for the opener, as Gabriel flicked a header home from Bukayo Saka's corner.