That statistic has been doing the rounds for some time but it still seems unreal to the German half of Arsenal's flourishing centre-back partnership.
More than two years after the Mertesacker-Koscielny axis last tasted defeat - a 2-1 reverse to Manchester United at Emirates Stadium - they have finished 31 matches together, winning 22 of them.
I think we have shown a lot of people who criticised us a lot over the last two-and-a-half years that we know each other much better now
More recently Arsenal have conceded just once in their last 11 home games but Mertesacker craves much more than eye-catching stats - he wants to back it up with silverware.
"It [the statistic] sounds not real for me," he told Arsenal Player. "When I first heard it, it sounded very weird. It's a good statistic but we have to build on that.
"I think we have shown a lot of people who criticised us a lot over the last two-and-a-half years that we know each other much better now and that we complement each other well, so it looks like that's a good partnership [with Koscielny].
"But I wouldn't say that's only us or the two of us. I think when I speak about our centre backs I want to include always Thomas Vermaelen because he's our captain and he's always vital for everyone. He's aware of situations, he gives us a boost, he came back from a heavy injury.
"The boss will rotate in the next couple of months and it's really important that we are all in good fitness and all in a good shape so we can continue our good form and good partnerships with the three of us."
Mertesacker and Koscielny first lined up together on September 10, 2011 for a 1-0 victory over Swansea City and the first of many clean sheets. The Germany international is anything but a carbon copy of Koscielny but, when it comes to successful partnerships, he thinks opposites attract.
"In this case I would say we have different qualities," said Mertesacker. "One is more mobile, one has more height. It fits absolutely well together because [these] days the centre backs are not just tall and just have to [deal with] long balls and to head these balls.
"I've played with many good centre backs with different qualities. But Laurent, he's one of the quickest players I've ever played with, one of the most mobile players, and he anticipates well a lot of balls so he has real strengths to be a good partner.
"For me it's easy to play alongside him. Hopefully he's going to say that to you as well when he speaks about me! We both take advantages from each other so that is the main key [to our success] I think."Copyright 2016 The Arsenal Football Club plc. Permission to use quotations from this article is granted subject to appropriate credit being given to www.arsenal.com as the source