Nemanja Vidic has warned Manchester United's Premier League rivals that they will be stronger in the second half of the season.
United trail leaders Manchester City by three points and were knocked out of the Champions League before Christmas.
But the United captain believes the club are starting to overcome injury problems that have hit the club.
Vidic, ruled out for the rest of the season, told the BBC: "How we finish is most important. We will be better."
United have been hit by injuries in defence, with Rio Ferdinand, Chris Smalling, Jonny Evans and Phil Jones having all missed games over the past month.
But Vidic, 30, told BBC North West Tonight: "I'm positive. We've had problems with injuries but it seems all the players are getting back and getting fitter.
"We will be better than we were in the first half of the season.
"It's not bad for the city of Manchester to have two teams competing for the title - as long as we finish in first place."
Fellow defender Smalling, 22, believes only Sir Alex Ferguson's side can take heart from the fact they are challenging for the title despite a number of injuries this season.
Smalling, now fully recovered from tonsillitis, told the club's website: "We've probably had more injuries than any other club in the league.
"Not many teams have lost players of the calibre of Nemanja and Darren Fletcher for such lengthy periods.
"And yet we're still going strong, we're still challenging for the lead."
England defender Smalling returned in the FA Cup victory against Manchester City then sat out Saturday's win over Bolton, but hopes to play at Arsenal on Sunday.
"People were starting to write us off," he added. "Instead of crumbling we went to City and beat them on their home turf, even if we made hard work of it in the second half.
"Winning that game showed a lot of character."
Meanwhile, United full-back Ritchie de Laet has returned to Old Trafford after his season-long loan move to Norwich was terminated five months early.