Chelsea manager Enzo Maresca has admitted Mykhailo Mudryk has been a slower learner than his teammates but praised the winger's performance in his side's 4-1 win over Panathinaikos.

It was an efficient yet thorough display in Athens to maintain the visitors' perfect start in the Conference League and the Ukrainian's contribution was key, scoring the second goal with a brave header as well as setting up two goals for Joao Felix.

Maresca previously challenged Mudryk to seize upon his selection in the starting XI and prove the worth of his £88 million ($A172 million) transfer fee, and those words were heeded as the 23-year-old had his strongest game of the season in the Olympic Stadium.

"We want the best for Misha, since day one we've tried to help him. Probably he's one of the guys that the learning process is more slow compared to the rest," said Maresca.

"But he's improving. I'm sure that slowly, slowly we're going to arrive where he will score more goals and to be more important for us."

Given the size and passion of the home support in the Greek capital this might have been expected to be the toughest of Chelsea's league stage assignments in this competition.

But they took the sting out of Panathinaikos with a goal midway through the first half before blowing them away with three in 15 minutes after the interval.

Former Manchester United winger Facundo Pellistri tapped in a consolation, but despite making 11 changes from the side that lost to Liverpool in the Premier League, Chelsea's dominance was never challenged.

Asked whether a club of Chelsea's size could ever prioritise this competition, Maresca said: "If we are a Champions League club, why are we in the Conference League? It's because in this moment we belong to the Conference League. Football in the end always puts you where you deserve to be."

Elsewhere, Socceroos Kye Rowles and Cameron Devlin both played full games as Hearts beat Omonia Nicosia 2-0 in Edinburgh.

Real Betis and FC Copenhagen drew 1-1 in Seville.

Jonathan Ikone's two goals led Fiorentina past St. Gallen 4-2 in Switzerland, while Iceland's Vikingur beat Belgium's Cercle Brugge 3-1 to record their first victory in Europe.

With AAP.