Lionel Messi scored either side of half time – both goals going through Thibaut Courtois’ legs – as Barcelona beat Chelsea 3-0 on the night.
He also bagged the away goal last month at Stamford Bridge that had earned Barca the edge heading into Wednesday’s clash.
And Blues manager Conte conceded the Argentina superstar was head above the rest in London and Catalonia.
“Tonight in the two legs, Lionel Messi made the difference,” Conte said.
“We are talking about the best player in the world. Over the two legs we were a bit unlucky.
“We hit the post four times. In our best moment today they scored.”
Chelsea had chances to score themselves but came up against a dogged Barcelona defence, while the visitors were themselves outdone by mistakes at the back.
Ousmane Dembele scored their second – his first goal since arriving from Borussia Dortmund in a £135m deal last summer.
“They were very clinical. We created many chances,” Conte said.
“We are talking about a player (Messi) that every season he scores 60 goals. We are talking not about a top player but a super top player. He made the difference.
“We have no regrets. I must be pleased for the commitment.
“They gave everything tonight. We didn’t deserve to lose 3-0.”
Chelsea felt they should have had a penalty in the second half when Marco Alonso was brought down in the box, only for the referee to wave away their appeals.
Conte said of the incident: “During the game, from the bench and for me it was a clear penalty on Marcos Alonso.
“We have to go and move on and to prepare for the game against Leicester (in the FA Cup) on Sunday.”
Meanwhile, Courtois conceded he should have done better with the two Messi goals.
“I’ve played against Messi a lot of times,” he said.
“I have already conceded goals like that before. The weakest point is between the legs for a goalkeeper.
“It is annoying, I cannot hide inside, I have to be a man and come out.
“I made some good saves too but we go out with conceding four goals from four mistakes.”