United sit seven points behind leaders Arsenal, but are unbeaten in their last 11 games ahead of their clash with Tottenham this weekend.
But dropped points against Southampton, West Bromwich Albion and latterly CardiffCity have prevented the champions from overhauling their rivals.
Evra says the frustration of those careless performances have left United’s players frustrated, but has backed them to slip into title form in the coming weeks.
“We were really upset about the result at Cardiff to concede a goal in the last second,” said Evra.
“We didn't make the most of the Arsenal win and that was why we were so disappointed about the Cardiff draw.
“We are in good form - but for that silly goal at Cardiff. We have not lost for a long time and we want to keep winning and keep winning - we cannot wait for Tottenham.”
While United are now gathering momentum under David Moyes after a frustrating start to the season, France international Evra says they cannot afford any more slip-ups.
“We cannot afford to lose in the league. If we had won at Cardiff it would have been a bit easier going to Tottenham, but now we cannot afford to lose at White Hart Lane,” said Evra.
“We cannot afford to drop too many points and that is why Tottenham is now a very big game.
“Every game from now on is a big game because we had a bad start.
“If you calculate the draws against Southampton and Cardiff, plus the defeat at home to West Brom, if we had won those matches we would be top of the league - that's why we're so frustrated and upset.”
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