The German says that the Gunners must learn from their defeats to their title rivals this season if they are to challenge for the Premier League again
Arsene Wenger's side looked set to challenge for the title in the early stages of the campaign before falling off the pace and then facing a battle with Everton just to secure fourth place.
A 3-0 victory over Newcastle on Monday strengthened the Gunners' grip on a Champions League spot - they would secure qualification with a win over West Brom in their next fixture - and Mertesacker feels that it would be the most that they merit.
|17/10||Arsenal are 17/10 with PaddyPower to win both halves against West Brom|
Arsenal suffered heavy defeats to title rivals Chelsea, Liverpool and Manchester City and Mertesacker believes that his team must learn from those games if they are to improve their league position in future.
"We have to learn quickly how to play and how to defend in the first 20 to 25 minutes," he added. "It was very similar in each game. The first 20 minutes, we lost some balls in the middle of the park, they got us on the break and that is something we have to look at next year."
However, with an FA Cup final against Hull City to come, Mertesacker argues that the season can still be a success for Wenger's side.
He said: "We can learn a lot about ourselves from this. Last year we managed to deal with an even more difficult situation. Ten games to go, no one expected us to be in the top four.
"This year, with a couple of injuries, we struggled heavily but we regrouped very well and how we managed this situation was even more important maybe than last year.
"Everyone knows we are in the cup final, we can secure Champions League football, so good targets to go for.
"Of course, we are happy to have a lot of players back and you can see the squad is getting stronger and stronger."