Johnsen hoping to prove his worth
The Norwegian international is out-of-contract at the end of the season and the defender fears his time at Old Trafford may soon end, having only played in 28 matches over the last two seasons, after enduring problems with his knee.
The Old Trafford club are reluctant to give Johnsen a new long-term deal until he proves his full fitness again.
Johnsen has been in Sir Alex Ferguson's line-up for the club's last four fixtures and impressed in a 0-0 Champions league draw against Bayern Munich on Wednesday.
However, Johnsen knows that he must continue to perform in the United squad until the end of the season if he is to have a chance to stay at the club, especially as Ferguson is in the market for new defenders for next season.
The 32-year-old might have been on his way out the exit door, had Ferguson decided to retire at the end of the season.
"It would have difficult for United to offer me a new deal if a new boss had been coming in. So I'm pleased Sir Alex is staying.
"United is my club and I want to stay but nobody has spoken to me about another contract.
"We'll just have to wait and see what happens up to the end of the season and take it from there.
"All I can do is my best until then and see what that brings.
"But it's not the important issue at the moment. I want to play games and the main thing is helping United at a vitally important time for the club.
"I'm not going to let the contract situation put extra pressure on me. There's enough to worry about in matches without adding to that burden."
The Norwegian felt a sense of embarrassment after winning a championship winners medal last season, playing only the last four matches of the Premiership season after being six months out.
Johnsen added: "Last season, everything was over when I came back. We were out of the Champions League and had already won and had already won the Premiership title.
"But this year couldn't be more different. I'm fortunate to return just as the season is reaching a climax.
"Every game is a final from now on and you need to be on top of your game. If I can get a championship medal this time, I'll feel like I've earned it more."
Johnsen was pleased with his effort against Bayern, despite the lack of entertainment in Wednesday's match at Old Trafford.
Johnsen said: "There weren't many chances and both teams tried to keep it tight at the back.
"It may not have been an exciting game for the fans, but against teams of Bayern's quality your concentration has to be spot on.
"Both teams were happy at the end to qualify for the quarter finals."
Meanwhile, United are determined to win their final Champions League group match against Boavista in Oporto next week.
The Red Devils would finish top and avoid both Real Madrid and Deportivo La Coruna in the quarter finals.
United boss Sir Alex Ferguson said: "We want to win that because we don't want to face any of the Spanish sides in the quarter finals.
"They are so dominant now and we would rather avoid them. It is a very important game for us."
Also, Wes Brown has revealed that his chances of being picked by Sven Goran-Eriksson for the England World Cup squad are remote.
The United defender has out since December with ankle and problems injuries and he told the club's official matchday programme: "I don't think I'll be in his (Eriksson) plans at the moment.
"I've just got to get back playing in the United first team before I start thinking about England."