The leaders had controlled the first half yet found themselves behind in stoppage-time when a Tom Ince corner hit Otamendi on the shoulder and flashed into the net. "They defend extremely well, they are very risky on the direct game".
Huddersfield goalkeeper Jonas Lossl blocked from City's Gabriel Jesus inside the penalty area.
Clarets defender James Tarkowski was penalised for his shove on Aaron Ramsey in the 91st minute and Sanchez made no mistake from the spot to clinch the Gunners just their second league win on the road this season.
"From outside it (the penalty) looked 100 percent".
"I haven't seven seen him", said the Arsenal boss, as quoted by the Metro. I'd have to watch again but there was one on Bellerin as well.
Reflecting on the game as a whole, Wenger added: "In the first half we didn't find our game, they stopped us from playing very well. Burnley defend extremely well and are very risky on the direct game". It's a frustrating defeat to take for Burnley, who defended well and is not the first time they've lost late on against Arsene Wenger's side either in recent meetings.
Arsenal revealed on their official Twitter account that Ozil will not feature due to illness.
Everton is now 16th, just two points clear of the relegation zone.
Arsenal appeared to have more goal immediately after the restart and saw Ben Mee block a good opening for Sead Kolasinac, before Lacazette forced Nick Pope into his first real save.
Charlie Austin scored two second-half headers, while Dusan Tadic and Steven Davis were also on target to give the home side a 4-1 victory over the Toffees.