Having missed the last three matches with a hamstring injury, the Spain international showed just how valuable he is to Arsenal, who moved to within three points of Premier League leaders Chelsea - with Bolton again to come at the Emirates Stadium on Wednesday.
"It is important for us not to lose any more players, especially him. He is just coming back now," said Wenger.
"We survived okay when he was not there but, in the period coming up, when we have so many big games, it is important to have him.
"If you watched the game, it is difficult to say how much we have missed him but you don't need to explain to anyone that it is important."
Asked if Fabregas was the best midfielder currently playing in the Premier League, Wenger added: "I do not see all the games but what is very interesting for us is Cesc gets stronger and stronger and has more personality on the pitch, like the whole team.
"He grows. He will be 23 this year - he is just starting."
Bolton manager Owen Coyle, in his first match in charge since leaving Burnley, could only marvel at the talent of the Gunners' captain.
"The quality of Fabregas, with the first goal when he bounced a one-two off Eduardo, he could play for anyone in world football," said Coyle. "He is such a top player."
Coyle was, however, pleased with his side's display as they created enough chances to have earned something from the game.
"I thought the level of performance was terrific," he said.
"What we offered for the duration of the match would, on another day, result in points - whether it be one or three.
"We were always in the game, particularly second half, and they weren't half-chances, they were real gilt-edged chances.
"We created chances from the first minute of the match and, if you analyse that game, I think we were deserving of a better result.
"We never got that break you need against these elite clubs - the first goal hit Matt Taylor on the back of the head and a couple of boys have fallen over when the ball has come into the box."