The one-time Gunners hero departed north London to rejoin boyhood team Barcelona in 2011 but struggled to nail down a first-team place before being sold to the Blues in July.
Fabregas played his first competitive match for Jose Mourinho's side on Monday, setting up two goals in a 3-1 Premier League victory over Burnley, but the Frenchman insists he does not regret missing out on his old player.
"I have no regrets that Fabregas [joined Chelsea]," Wenger told reporters.
"My only regret is that he left us in the first place."
Arsenal have a well-stocked midfield even without Fabregas, with few players in the top flight drawing as much praise as Aaron Ramsey over the past 12 months, and Wenger is excited about the Welshman's progress.
"Aaron Ramsey has a different style to Fabregas but he has huge potential," the Gunners boss enthused of the 23-year-old, who was sent off against Besiktas on Tuesday.