Mike Penders is one of European football’s highest-rated young goalkeepers after impressing on loan at Strasbourg last season. And the 21-year-old has recently been given a chance to show what he can do at Chelsea, starting three consecutive matches after Emi Martinez broke his jaw.

Penders’ introduction to the starting XI has not been entirely smooth, with a costly error against Tottenham, but he produced a more encouraging display against Liverpool in the EFL Cup. Penders took another step forward against Manchester United, keeping a clean sheet with an excellent performance. The Belgian’s unusual goalkeeping trick has now emerged.

The goalkeeping hack Mike Penders used against Man Utd

One of the secrets behind Mike Penders keeping a clean sheet against Manchester United was a stash of Vaseline smeared on his goalpost at Stamford Bridge, according to The Daily Mail. The Chelsea goalkeeper used the petroleum jelly to add extra grip to his gloves, particularly before facing corners, and was spotted rubbing his hands with the substance shortly before claiming a Bruno Fernandes cross.

It might sound like an unusual method, but goalkeepers have used the trick for generations and it is perfectly legal. Former Premier League goalkeeper Ben Foster has previously praised its benefits, and he learned about it from Joe Hart, who in turn picked it up from Kasper Schmeichel.

Penders is believed to have learned the technique from Karl-Johan Johnsson, who was Strasbourg’s second-choice goalkeeper last season. The Swedish veteran even has a YouTube video explaining the benefits of using Vaseline, which has more than 50,000 views.

It is unclear whether Penders used the same method during Chelsea’s 2-0 defeat to Tottenham, when he punched a corner into his own net. However, the 21-year-old has since responded with impressive displays against Liverpool and Manchester United, including a stunning save to tip Bryan Mbeumo’s powerful effort onto the crossbar.

Clean sheets have been hard to come by for Chelsea, making Penders’ contribution particularly welcome. If selected against Sunderland on Sunday, he may well continue using his strange technique. It will also be interesting to see whether Emi Martinez adopts the same approach when he returns to the team.