Mertesacker said the two speed merchants were always racing each other in training.
“Hector and Theo Walcott were locked in a constant battle for clocking up the fastest sprint numbers at Arsenal,” Mertesacker told The Athletic.
“It was a big rivalry — a bit like (sprinters) Carl Lewis and Ben Johnson in the 1980s.
“I always did better at those running tests than people expected, over the first ten metres at least.
“I only needed three long steps to get there. Over 30 metres, it was more difficult for me.
“But Hector and Theo could not take being second-best.
“If one of them finished ahead by second or so, the other one would insist on trying again to do a faster time. Hector was just that little bit faster.”
Mertesacker alos lauded the fantastic technical ability of Lukas Podolski at Arsenal.
“Lukas was a phenomenon,” he continued.
“The first thing he’d do after getting on to the pitch for training was to smack the ball cross-field into the far side of the goal and start laughing out loud.
“Every single time. No warming up at all. Full power.
“The fitness coaches were always a little worried but it was never a problem for Lukas. His volleys, his shooting from the edge of the box… unstoppable.”