LONDON (REUTERS) - Arsenal have not lost an English Premier League match where Per Mertesacker and Laurent Koscielny have completed the full 90 minutes for more than two years - a statistic the German defender struggles to comprehend.

A 2-1 reverse to Manchester City on January 22, 2012 was the last time the league leaders lost with the pair at the back, a streak that now stands at 32 matches, including 23 wins.

Arsenal have conceded 21 goals in 24 league matches this season, second only to third-placed Chelsea, and they have let in one goal in their last 11 home games.

"It (the statistic) sounds not real for me," Mertesacker told the club's website. "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."

Mertesacker and France international Koscielny have both come in for criticism during their time at the London club, but in tandem they have become one of the league's most reliable centre-back pairings.

Their form has meant club captain Thomas Vermaelen has struggled to force his way into the starting line-up.

Yet Mertesacker said rotation would be important with a tough run of fixtures approaching, including league matches against Liverpool, Manchester United, Tottenham Hotspur, Chelsea, Manchester City and Everton in the next two months.

"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 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."