Thomas Tuchel hailed Romelu Lukaku's goal-scoring "personality" as central to Chelsea's unbeaten Premier League start.

Belgium hitman Lukaku fired a fine double for his first Stamford Bridge goals, as the Blues swept past Aston Villa 3-0 in west London.

Mateo Kovacic teed up Lukaku's first strike then dinked home a neat finish of his own, with Chelsea moving second in the table after three wins and a draw.

Boss Tuchel heaped the praise on £98million summer recruit Lukaku, who has now hit three goals in as many league games for the Blues.

"Today he was the difference, he adds another profile in our squad," said Tuchel.

"He has the kind of personality and self-confidence, he knows what he's up to, he wants to score and help the team, and he has the confidence and the composure to do it.

"They were two very difficult goals, there were no easy tap-ins and he made the difference for us to get three points today.

"He adds something to the group that we did not have in this capacity so far.

"So he was very, very good, and we are very happy."

Manchester United's Cristiano Ronaldo and Chelsea man Lukaku both bagged a brace in Saturday's Premier League action, with both forwards having dominated Serie A last term.

Lukaku matched Ronaldo's United haul, but Tuchel would not be drawn on any potential battle for this term's golden boot.

Asked who would bag more league goals between Lukaku and Ronaldo, Tuchel said: "I couldn't care less, as long as Lukaku scores for us!

"Honestly, I know that you would like to have a good answer, but unfortunately I don't have one.

"Romelu wants to score for Chelsea and that's exactly what he did today.

"That's why he's here, he's not shy to speak this ambition out loud, because he's full of confidence and the kind of personality who can handle it. This is what he showed today."

Saul Niguez made his Chelsea debut after his deadline-day loan switch from Atletico Madrid, but the Spain midfielder struggled and failed to meet the Premier League pace.

Tuchel replaced the 26-year-old at half-time with Jorginho, and admitted that switch proved a difficult call.

"It was a hard decision, but he was struggling, and I take the responsibility for that," said Tuchel.

"I put him into a difficult match after a national break, and it was hard to adapt to the physicality and in general for him, intensity and high pressing.

"It was also a bit hard for him to adapt to our system. So we thought to give a bit more stability and switch the shape to 5-3-2 in the second half with Jorginho.

"It was a tough one but I hope he can accept it's on my responsibility. In training he looked like he had no problem to adapt but today was very, very intense. He had some easy ball losses which I thought was very, very unusual for him.

"So before he lost any confidence I thought it best to take him off."

Dean Smith was left to rue several early missed opportunities, but insisted his Villa side can keep heads held high.

"I'm frustrated with the scoreline, but we didn't take our moments today," said Smith.

"We don't have to come to Chelsea as we would have perhaps two years ago and sat with a deep block and look to counter attack.

"I feel we can actually now go and ask questions, we did that in the first half.

"The second goal, big mistake, took the wind out of our sails somewhat.

"There's an awful lot of belief in this squad, and we'll take it forward despite the scoreline today."