Victory sees Wenger's side pull two points ahead of Chelsea, but have played two games more than their West London rivals.
The Frenchman said that his team cannot afford to drop points in their final two games in order to qualify for the Champions League.
"We had a great start and surprised QPR, but then they came back strongly and showed they have no fear," Wenger told BBC Sport. "I think they've got a good chance of coming back up to the Premier League.
"We're on a very strong run and want that to carry on until the end of the season. Football is unpredictable but for three months we've been in a position where we cannot drop points."
Arsenal take on Wigan Athletic at home in their next match before a final-day trip to face Newcastle United.