Antonio Conte conceded Chelsea let the "complete player" slip from their grasp after watching Kevin De Bruyne inspire Manchester City to an excellent win over the Premier League champions.
De Bruyne was named man of the match after his sublime 67th-minute strike gave City a 1-0 triumph at Stamford Bridge on Saturday.
Pep Guardiola's league leaders are six points better off than Chelsea, who were undone by a player who made a mere three top-flight appearances for them before being jettisoned to Wolfsburg in the Bundesliga during Jose Mourinho's second spell as manager.
"I don't know, honestly, what happened in the past," a rueful Conte told reporters.
"But for sure we are talking about a top player. He's a really good player, a complete player. He's good technically, fast."
De Bruyne also scored a similarly impressive breakthrough goal in City's 2-0 Champions League win over Shakhtar Donetsk this week to open his account for the season.
The Belgium international has operated in a slightly deeper role under Guardiola than previous boss Manuel Pellegrini and, while not as prolific in goalscoring terms as during his debut season at the Etihad Stadium in 2015-16, De Bruyne's manager praised his selflessness and fleshed out Conte's complimentary assessment.
"He can do absolutely everything," Guardiola said. "With the ball, he's a guy who can play different positions, go to the channels, assist long or short.
"After, without the ball he's the most humble, the most shy guy. He says if I have to run 100 kilometres for the team, I will do that. It's not easy to find that with this kind of talented player.
"That’s why he's one of our captains. I think he makes [City take] a step forward and people feel comfortable having him on the pitch."