Romelu Lukaku can turn Timo Werner into the goal machine Chelsea always thought the German would become, according to Thomas Tuchel.

The Blues' £97.5million investment in Lukaku, a player they offloaded to Everton for £28m seven years ago, has been one of the most eye-catching transfers of the window.

After starring with Inter and Belgium, Lukaku looks to be in the prime years of his career, ready to transfer his own scoring form from Serie A to the Premier League.

He could make his second Chelsea debut at Arsenal on Sunday, and head coach Tuchel sees Lukaku bringing his influence to bear across the Chelsea frontline, including spurring on Werner to improve on his ho-hum first year in English football.

"This can be a big upgrade for him, to have Romelu, who likes to be in the centre of the pitch and to fight physically with defenders," Tuchel said.

"He can create spaces for Timo, first of all from a position a bit wider than he used to play for us in the last season, to play around Romelu who is like the reference as a number nine, a reference for the attack.

"Hopefully, it gives Timo the space to play around him, to feel a bit more freedom, make it a bit easier to find the dangerous spaces and start scoring again."

Werner scored just 12 goals for Chelsea last season, failing to get close to an expected goals (xG) total of 21.07 that reflected the quality of his chances.

Those goals came at a rate of one every 318.83 minutes, and his shot conversion rate of 10.17 per cent fell well short of expectations.

At the same time, however, his assists total of 11 far exceeded an expected assists (xA) total of 4.48, and he finished the campaign as a Champions League winner, meaning it was not all bad for the former RB Leipzig forward.

The only player from Europe's top five leagues to score at least 10 goals in all competitions but have a worse conversion rate than Werner was, perhaps surprisingly, Manchester City playmaker Kevin De Bruyne (9.43 per cent).

Lukaku's 30 goals for Inter came from a healthy 24 per cent conversion rate, while higher up the list Erling Haaland of Borussia Dortmund netted 41 goals with a 31.54 per cent strike rate. Haaland was one of the strikers linked with Chelsea before the club moved for Lukaku.

Behind the forwards, Chelsea have a Ballon d'Or contender in midfielder Jorginho, who followed Champions League glory by helping Italy win Euro 2020.

Jorginho and Liverpool's Fabinho were the only players in the Premier League last season to have a passing accuracy of at least 89 per cent, while winning 50-plus tackles and making 40-plus interceptions.

Seven penalties from Jorginho also came in handy for Chelsea, and Tuchel, who arrived after a spell in charge of Paris Saint-Germain in mid-season, has been highly impressed.

"I think Jorgi is a strategic player," Tuchel said. "He can play advanced, he knows what to do in ball possession, he can imagine what's going to happen one or two passes ahead.

"He knows where to help out in short and longer distances, when to switch the play and when not to. He has a good sense of rhythm and, if you watch him separately, in isolation, he lacks maybe the pure physical ability that makes him the number one candidate to be the number six in the Premier League, you'd think, but once you have him in a structure he is very well organised in his game, organises all the environment around him, which helps him, then he can show his true abilities in controlling the rhythm of a game.

"On top of that too, he is a top guy. He is funny, he has a big smile on his face every single day. You can have chats with him, have a laugh every single day with him, because he's up for it. He is in love with this game."

Tuchel said Chelsea found "momentum" last season, which carried them to their season-ending success, describing them as "a real team with exceptional spirit".

Now a Premier League title is the obvious target, and Tuchel says continuing success will only come through "consistency and the daily process".

"We will not lose focus by putting expectations on people's shoulders. We have high expectations ourselves; we need to live up to those," said the former PSG boss. "Once we lower our levels, we could lose every single game in the Premier League. That is the reality."