Arsene Wenger's side took a significant step towards securing a top-four finish with a 3-0 win over a lacklustre Newcastle side at the Emirates Stadium on Monday night, where fit-again record signing Mesut Ozil scored one and created another.
Arsenal are now four points clear of Everton with just two games to go, with the Toffees having been beaten by Southampton at the weekend.
The Gunners will be guaranteed a place in the Champions League qualifiers for the 17th consecutive season should Everton come unstuck again when they tackle Manchester City on Saturday, or Arsenal beat West Brom 24 hours later before attentions turn to ending the club's trophy drought in the FA Cup final against Hull at Wembley
As positive an ending as the campaign may yet bring, Mertesacker cannot help but reflect on what might have been, with Arsenal at one stage seven points clear of current leaders Liverpool at the top of the table before paying a heavy price for a series of poor results against their direct rivals.
"We have struggled heavily with a couple of injuries, but we have regrouped very well and how we managed the situation was maybe more important than last year, so securing Champions League football was another test for us," he said.
"It is not done yet, Everton play Manchester City on Saturday, but we have it in our own hands.
"However, everyone wanted us to get further up, especially the fans, and we were top of the table for a long time.
"Everyone dreamed about the title, but it takes more than staying top until the winter period.
"We could not afford those (losses) in big games against big teams, so we did not deserve to be in the first three
That is something we have to manage much better next year.
"The (defeats in the) early away games (at Manchester City, Liverpool and Chelsea) killed us this year
Hopefully we can learn from that.
"Everyone questioned our qualities, but how we came back as a team, that makes us stronger for the future."
Mertesacker added: "We are in a cup final and it is important to secure Champions League football, so these are good targets to go for.
"We are happy to have a lot of players back
The squad is getting stronger and stronger."
Arsenal midfielder Alex Oxlade-Chamberlain missed the Newcastle match because of a groin complaint which although not serious will leave the England man touch-and-go for the FA Cup final.
Newcastle, meanwhile, will head back to north-east England looking to regroup following what was a sixth straight defeat which has left their place in the top 10 now under serious threat.
Alan Pardew, who returned to the dugout following a lengthy touchline ban, accepts the supporters have a right to voice concerns following a miserable run of just 13 points from 17 league games since the turn of the year - with many of the 2,000-strong Toon Army calling for the manager's head during Monday's night's latest feeble offering.
Midfielder Dan Gosling said: "Having the manager there on the touchline again was a great help, but ultimately it is the players who cross the white line who have to do the job, and again at Arsenal, we did not do that.
"We have lost some games where we should not have, but we can't just keep saying that.
"We are disappointed, but we will go again now on Saturday and have a cup final against Cardiff.
"The fans have always been tremendous and we get a great travelling army, and at home we will need them now more than ever to push us over the line."
Source : PA
Source: PA