Arsenal manager Arsene Wenger has no regrets over his decision not to re-sign Cesc Fabregas this summer.
Spain midfielder Fabregas, 27, made an impressive Premier League debut for London rivals Chelsea as they won 3-1 at Burnley on Monday.
Arsenal had a buy-back option on Fabregas, who left for Barcelona in 2011, but decided not to exercise it.
"I have no regret about that at all. My regret is that he left," said Wenger, whose side play Everton this weekend.
Fabregas, who played 305 games for the Gunners, eventually joined Chelsea on a five-year deal, ending his three-year stay at Barca.
The midfielder played a part in all three goals against Burnley and Wenger admitted it was "strange" to see his former player in the blue of Chelsea.
"It was difficult for him to leave us, but after that you accept he can move to some different clubs," he added.
|Cesc Fabregas factfile|
|Born Spain, May 1987.|
|Joined Arsenal from Barcelona as a 16-year-old in 2003.|
|Scored 57 goals in 303 games for the Gunners, and won the 2005 FA Cup.|
|Joined Barcelona in 2011, scoring 35 goals in 129 appearances.|
|Helped Barcelona win La Liga in 2013 and Copa del Rey in 2012.|
|Scored 13 goals in 89 appearances for Spain, including winning the 2010 World Cup and 2012 European Championship.|
Wenger believes Wales midfielder Aaron Ramsey, 23, is more than filling the void left by Fabregas.
"What is good in life is that someone moves out and someone else takes over and he has developed," he said. "He is younger than Cesc and the potential is there to get more out of him."
Wenger added that Ramsey's dismissal during Tuesday's 0-0 draw at Besiktas and an ankle injury suffered by captain Mikel Arteta in the same game had left him considering a move for a defensive midfielder.
Wenger admits he does not know how long Arteta will be sidelined, adding: "He had a scan on Wednesday afternoon. I haven't got the result... I don't know how long he will be out for. We will be a bit short, of course.
"If it is a long-term injury, that puts us in a position where we have to be creative.
"We are open as well to any opportunity, until the end of the transfer window, who can strengthen our defensive department in quality and number."
Arsenal expect to be boosted this weekend by the return of their trio of German World Cup winners, Per Mertesacker, Lukas Podolski and Mesut Ozil.