Chelsea head coach Thomas Tuchel hailed N'Golo Kante after the Blues star came off the bench and scored in the 3-0 Premier League victory over Tottenham.
Kante, Thiago Silva and Antonio Rudiger were on target in the second half as Champions League holders Chelsea blew away London rivals Tottenham in Sunday's derby.
Silva opened the scoring four minutes into the second half before fit-again midfielder Kante doubled the lead approaching the hour mark, and Rudiger added a third in the second minute of stoppage time.
Three of Kante's last four Premier League goals have been scored from outside the box, after netting just one of his first seven in the competition from range.
Tuchel lauded the France international as Chelsea moved top of the Premier League on goal difference.
"If you have N'Golo [Kante] on the bench and you want to step up in exactly these patterns of the game, he's the best player to bring on because he's unique and he can change any momentum," Tuchel said.
"[With him] you have everything that you need in midfield: you have work rate, intensity, ball wins, skillful play. Off the ball, with the ball, dribbling, even a goal. I see this every day in training and it's hard to believe how good he is.
"He doesn't make faults and reduces the number of ball wins. He plays excellent in every possession game that we have in training. He's a unique guy and I have no words for him.
"We were strong in midfield together with Jorginho and [Mateo] Kovacic in the second half. N'Golo is N'Golo - fantastic."
Chelsea have won each of their last six away league London derbies – the club's longest such streak in their league history.
The Blues have only lost one of their 12 away games in the Premier League under Tuchel (W8 D3) – no Chelsea manager has lost fewer away games in their first 12 outings in the competition (level with Guus Hiddink and Jose Mourinho).