PSG goalkeeper Marcin Bulka has lifted the lid on how Petr Cech maintained his focus while playing.

Cech is now a football advisor for Chelsea, but before he left to join Arsenal in his veteran years the Czech Republic great spent time working with a young Bulka at the Blues.

Bulka left Chelsea for PSG last summer and revealed the unusual way his former teammate prepared for games.

He told Foot Truck: "He was always super focused.

"The Chelsea coaches told me that he used to do math exercises before the games because it helped him focus."