Manchester City midfielder Frank Lampard says he is not surprised by Cesc Fabregas and Diego Costa's impressive start to their Chelsea career.
The Spain international duo were added to the west London club's squad in the summer transfer window. While the striker arrived from Atletico Madrid, Jose Mourinho snapped up the services of the former Arsenal skipper from Barcelona.
Costa is currently the leading goal scorer in the Premier League with nine goals after seven matches. His compatriot has already managed seven assists in domestic competition and is heading the assists charts.
Fabregas' form has helped Chelsea sit on top of the table with 19 points after seven matches. The Blues legend has already played against his former club during City's 1-1 draw at the Etihad, where he scored for Manuel Pellegrini's side.
Lampard says his former City teammates are aware of the qualities possessed by Fabregas and Costa.
"I've watched their games from afar and neither of them are a surprise to me. I knew Cesc Fabregas and played against him at Arsenal. He knows the Premier League and is a top, world-class player," Lampard told Sky Sports.
"We watched Diego Costa on video before we played Atletico Madrid in the semi-finals of the Champions League last year and you could have probably sat there for three hours looking at his running, his goals and the things he was doing.
"I thought 'he's some player' and Chelsea have signed that player. I know Vincent Kompany pretty well now and he saw playing against him as a challenge."
"Diego Costa probably walked into this league and thought it's very good, but the Man City game was the one game where people stood up and fought back at him. He got through once and hit the post and that's the quality of the player," Stamford Bridge favourite added.