The German defender was speaking to Arsenal Player after Arsenal's hard-fought win over Swansea City on Saturday that sent the Gunners back to the summit of the Premier League.
I can feel that everybody wants it and everybody is capable of doing more than usual so you can feel the special team spirit at the moment.Per Mertesacker
And when Mertesacker was asked about his link-up with Koscielny, the French defender was conveniently on hand to return the compliment.
"I have a good opinion about him and our partnership at the moment is a good one but we have to keep proving that," said Mertesacker.
"He is a good partner, we talk a lot on the pitch and it's very important for a centre back to speak a lot and communicate with our midfield, so today we won and we are happy with this," Koscielny replied.
Mertesacker, who has captained Arsenal in five of their first six league games this season, thinks the key to the Gunners' early season form is a special spirt in the dressing room.
"I can feel that everybody wants it and everybody is capable of doing more than usual so you can feel the special team spirit at the moment.
"We lost a lot of players at the start of the season and we have to replace four good wingers who can make the difference but you can see Serge Gnabry stepped in today and scored his first goal for Arsenal.
"Aaron Ramsey is stepping in all the time and you can see how everyone celebrates together, there is a proper mentality building up that we can be proud of. That's our momentum and we need more of that."Copyright 2017 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