Sir Alex Ferguson says Manchester City's dominant start to the Premier League season counts for nothing at this stage of the campaign.
City led the table from mid-October until 11 March, but United are now three points ahead.
"They were playing great football in the first half of the season," said the Manchester United manager.
"We felt the brunt of it when they beat us 6-1," he added. "But a season lasts for a bit longer than three months."
United and City, who are chasing a first top-flight title since 1968, found themselves neck-and-neck at the top of the table in the early part of the season.
Ferguson's men were ahead on goal difference until 15 October, when they drew at Liverpool and City beat Aston Villa.
The following weekend, City thrashed United at Old Trafford to open up a five-point lead, which they held until the Red Devils beat Wolves on 10 December and the Blues lost at Chelsea two days later.
Roberto Mancini's side remained top until they lost at Swansea on 11 March and United overcame West Brom.
"Hopefully we can stay there but we also know that football can turn on you and bite you," said Ferguson, who has guided United to 12 Premier League titles.
"That's the point about experience - hopefully it helps us.
"We have a small advantage, it's not a great advantage. That can be changed in one game. So we just have to take each game as it comes."
United last lost a league match on 4 January and, with eight games remaining, including a trip to the Etihad Stadium on 30 April, Ferguson is confident his squad has the nerve to secure the club a 20th top-flight crown.
"Most of them have had experience [of this stage in a title race]," the Scot explained. "Rio Ferdinand, Patrice Evra, Ryan Giggs, Paul Scholes, Michael Carrick, Wayne Rooney.
"There are young ones who are not accustomed to it like Danny Welbeck, Ashley Young, David de Gea, Phil Jones, Chris Smalling.
"Other boys like Fabio da Silva and Rafael da Silva have been here for two or three years, so they're used to being involved. Both have played in European finals and hopefully it helps them in the run-in.
"I think Ferdinand, Giggs, Scholes and Carrick help that situation. If they were to lose their nerve then we would be in trouble, but I don't expect that. They're well accustomed to it."
Ferguson also insisted contentious refereeing decisions even themselves out over the course of a season.
Fulham were denied a late penalty in the 1-0 loss at Old Trafford on Monday.
"It evens itself out over a season and that will never change," said Ferguson. "You get breaks here and there. Every club gets good breaks, bad breaks."