Midfielder Mikel admitted the Blues would almost certainly have to win the Champions League final on May 19 if they are to qualify for next season's competition after Wednesday night's 2-0 home defeat to the Magpies.
The result left Roberto Di Matteo's men four points adrift of the Barclays Premier League top four with just two games remaining and put a serious dent in the caretaker manager's hopes of being appointed full-time.
By the time Chelsea next play in the league, they could already be condemned to finishing fifth or six if two of Newcastle, Tottenham and Arsenal win this weekend.
The Blues cannot afford to wallow in Wednesday night's defeat if they are to beat Liverpool in Saturday's FA Cup final at Wembley and stay on course for one of the greatest seasons in their history.
Acknowledging beating Bayern Munich at the Allianz Arena in just over a fortnight was Chelsea's only realistic hope of avoiding failure to reach the Champions League for the first time since Roman Abramovich bought the club, Mikel said: "Now we have to concentrate.
"Everyone is going to say that the only chance we have now is to win the Champions League final.
"It is what everyone wants, it is what the fans want and it is what we want.
"But we have to make sure now that we win on Saturday in the cup final and make sure that we don't let the cup final go past us."
Chelsea picked the wrong time to produce arguably their poorest performance since Di Matteo took charge, with Newcastle thoroughly deserving their first league win at Stamford Bridge since 1986.
The Magpies gave the Blues a dose of their own medicine, striking with ruthless efficiency thanks to one of the best braces you could ever hope to see from Papiss Cisse.
Mikel said: "It was just one of those days.
"We played Barcelona the other day. They they created God knows how many chances and they couldn't score, but we scored. This is football.
"We have to forget about it, go back to training and go back to what we have been doing up until now and just make sure we put it right on Saturday."
Mikel said of Cisse's goals, the second of which was a jaw-dropping 25-yard, half-volleyed banana shot from the corner of the area: "First one wasn't bad. Second one, as well, wasn't bad."
He added: "It wasn't like they beat us hands down. I think we had more possession of the ball.
"We just couldn't put the ball in the back of the net. We didn't create as many chances as we wanted.
"I think they had three shots and two goals.
"We were below par and we didn't play as well as usual.
"We have a cup final on Saturday. I think we should look forward to that and just forget about this game."
Di Matteo's top priority upon his appointment was securing Champions League football next season.
His likely failure to do so via the Premier League is the result of Chelsea's inability to beat any of the teams in the top half of the table in five matches against them.
A punishing run of fixtures in the league and cup meant something had to give in terms of team selection and, since qualifying for the Champions League semi-finals, Di Matteo has decided it would be the league.
However, his decision to play all three of Juan Mata, Frank Lampard and Ashley Cole in Sunday's thrashing of QPR but to rest the trio on Wednesday night arguably backfired.
Mikel told Chelsea TV after what was only the Italian's second defeat in his 17 games at the helm: "When the manager makes changes like this, sometimes it's good.
"He's been making changes and it's been working.
"We have been playing well, we've been creating chances and the team spirit has been there."