The Gunners won both matches last season by virtue of last-gasp goals - a Sanchez spot-kick also proving decisive at Emirates Stadium in January - and the Chile global repeated the feat after James Tarkowski was adjudged to have pushed Aaron Ramsey.
Arsenal struggled to create clear-cut chances despite their dominance of possession and Wenger praised Burnley's approach in his post-match press conference.
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.
Arsenal take on a Burnley side at Turf Moor who have won their last three league games.
"The doctor came to see me and said he [Ozil] had to travel back home, he was in the hotel with us", Wenger told a news conference.
"It looked a clear penalty". He was pushed in the back, he has a problem in his neck from the push.
"In the first half we didn't find our game".
Instead, Dyche's men were left to contend with yet another heartbreaking defeat to a team against which they have now lost 1-0 in each of the past three Turf Moor meetings.
And Wenger was very complimentary over Burnley's resolute defence.
"I've got this as a draw again".
But Chile forward Sanchez stepped up to seal Arsenal's second successive league win with his fourth club goal of the season.
The Clarets began with the confidence expected of a side chasing a fourth straight top-flight win for the first time since 1968, and Robbie Brady's excellent 10th-minute cross only just eluded the diving Ashley Barnes.
They're left in seventh place but despite the disappointment, they sit comfortably in a position that is still well above expectations.
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