Mourinho joked with reporters following United’s 3-1 win at the Emirates on Saturday after Lacazette played 90 minutes, despite Wenger saying he would “certainly” miss the game.
The Arsenal boss insisted he is always honest and maintained that he thought the France international striker would not be fit to start.
When asked about Mourinho’s comments, Wenger said: “I thought he wouldn’t play but in the end he could play.
“What did you want me to do, to leave him at home?
“I’m always honest. I thought he wouldn’t play, that was I had been told and after he had a test on Friday morning he went to the game and we were not sure if he would play.
“But, he tried and he played. That’s part of football.”
Arsenal host Bate Borisov in their final Europa League group game on Thursday, having already successfully sealed a place in the knockout stages by winning the group.
Shkodran Mustafi will miss the game with a thigh injury sustained in the United game, but Theo Walcott and Jack Wilshere are expected to feature in a much-changed side.
Wilshere, who has featured in all of the Gunners’ Europa League games this season as he continues to push for a permanent place in the starting line-up following an injury lay-off, joked on Twitter on Tuesday he had made it through a family ice skating trip unscathed.
Asked about the midfielder’s excursion, Wenger joked: “It’s not ideal, but for your balance it’s not bad. For a footballer, I don’t think it’s great.”
The Arsenal manager also insisted that Walcott will remain at the club after the January transfer window and praised him for his efforts on the training pitch.
“He works very hard to come back into it,” Wenger said. “He was sick a few weeks ago but overall in training, he looks very sharp. I’m sure he will show that tomorrow.”