Arsenal defender Mertesacker: Premier League best in world - a test every week
"Playing against Andy was a great test," he told the Sunday Express
"He plays very fair and he's a good guy. That's what makes you proud of the game in England - to compete against players like him who are fair and don't want to injure you, but at the same time who want to fight.
"It was a lesson; a good lesson. And it was a victory for me - and that is what is vital for every player. You want good competition and you want to win. That makes you proud - and positive for the future.
"You know, the German Bundesliga has improved in the past few years and it is quite a good league, but the best in the world in my opinion is the Premier League. That is because of the physical strength. You have to focus on every single tackle and contest in each match.
"There were quite a few games last season when I didn't have enough focus on tackling. I had to learn it, and learn it quickly, to cope with the physical stuff.
"In Germany it was more about anticipation and positioning and covering team-mates. In the Premier League you have to focus more on your body and be ready for whatever comes at you, the one-on-one battle with the opposing striker. It's fun."