Manchester City midfielder Ilkay Gundogan says it comes as no surprise to see Chelsea's two new German recruits Timo Werner and Kai Havertz struggling on their debut Premier League season.
The two Germany internationals were Chelsea's most expensive signings over the summer - both arriving from the Bundesliga - but have struggled to make a sustained impact so far this season.
Werner, who has four goals and five assists in the league this season, is on a run of 11 games without scoring for Chelsea in all competitions and has said he is having a difficult time adapting to life in the Premier League.
Meanwhile, Havertz has also failed to be productive since his arrival, managing just one goal and two assists in the league, with Chelsea boss Frank Lampard last month saying patience is required when it comes to the 21-year-old.
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Gundogan, having made the same transition when he joined City from Borussia Dortmund in 2016, knows just what his Germany team-mates are going through and is confident they will show their worth at Chelsea.
"They have two new German players who have tried to adapt as well as possible," Gundogan told Sky Sports News ahead of Sunday's trip to Chelsea.
"In general, I think it's not easy to adapt quickly to the Premier League when you come from a different country and now with the situation going on I think it's just even harder.
"So I think it's quite normal that they are struggling a little bit, but they both have incredible talent and I'm sure they will both be able to prove it in this league."
'Open title race makes this season so special'
Gundogan was impressed by Chelsea's summer spending and expects Sunday's opponents to be challenging alongside City all season in what he calls a "very open" title race. Chelsea and City are among the chasing pack at the moment, seven points off top spot, although the Manchester club have two games in hand.
City are without five players for the trip to Stamford Bridge after an outbreak of coronavirus in the squad which saw their match against Everton on Monday postponed.
Despite travelling with a weakened squad, City will know Sunday's match is a good opportunity to elevate their position in the table with Chelsea struggling for form, winning just one of their last five matches.
Gundogan was part of the City teams that won back-to-back Premier League titles under Pep Guardiola and, after watching Liverpool dethrone them last season, the Germany international is determined to get City back to the summit of English football.
"There's not one team that is dominating, not just in England but across Europe," Gundogan said.
"All leagues in the world they seem very open at the moment and it's quite exciting I think. In the Premier League it is exciting for all of the clubs, the fans, so let's see what is going to happen.
"Obviously you want to win games and you want to get back to that first spot but everyone is challenging and competing with everything that they have. That's what makes this Premier League season so special.
"Like every year Chelsea have a great squad with incredible players, they are a great team and they have a really ambitious manager so I feel like they will really challenge us. Not just at the weekend but also generally in the league.
"They got some really talented, young recruits in the summer, spent a lot of money and got some really good players so I think they will do well. They've done well, of course they are also a team that struggles like everyone does but they have a lot of quality and it's going to be a great game on Sunday."