Man United's Wayne Rooney (C) and Robin van Persie (R) at Old Trafford on December 15, 2012
Manchester United manager Alex Ferguson believes that his team's trip to Swansea City in the Premier League on Sunday is the start of a pivotal run of matches.
United go into the weekend three points clear of second-place Manchester City, who defeated Reading 1-0 on Saturday.
Ferguson's side then host Newcastle United and West Bromwich Albion before travelling to Wigan Athletic on January 1.
The United manager believes that if his team are in the same position when they travel to the DW Stadium, they will have taken a major step towards winning a 20th league title.
Ferguson said: "We have every right to expect a challenge. I think that's what we are good at. That's why I'm looking at December as an opportunity to gather points and make sure we are top of the league come New Year's Day.
"And if we are top of the league on New Year's Day, you know well -- and everyone else knows well -- that we're going to be in the ball park at the end of the season.
"We know there are going to be challenges -- it could come from Chelsea, too -- but I think City and ourselves will be battling it out (for the title)."
Ferguson, whose team have won 10 of their last 11 league games, has been impressed by the progress of Swansea, who are now in their second season in the Premier League.
Manager Michael Laudrup has continued the work of Brendan Rodgers, who left for Liverpool in the summer, and Ferguson says United will not take the Welsh side lightly.
"We've seen the results Swansea have had and the progress they've made as a football club and the way they do it is the important thing for me," he said.
"They try to play and have the courage to play their football, which is good. At this time of the year, all of these games are challenges because they come thick and fast now.
"Utilising the squad and picking the right teams will be important and hopefully we can get through it and be in the same position we are now."
Jonny Evans is set to return from a hamstring problem but may not be risked at the Liberty Stadium.
Midfielder Michael Carrick is also a minor doubt after being withdrawn at half-time in the 3-1 win over Sunderland last weekend with a hamstring injury.
Brazilian defender Rafael misses out again with a hamstring injury, Japanese midfielder Shinji Kagawa has yet to return from knee trouble, and winger Nani still has a hamstring injury.
After hosting United, Swansea head to Reading and Fulham before a home game against Aston Villa.
Laudrup believes that beating Villa would be more important in the quest to improve his team's league position, but he wants to take the scalp of the Premier League leaders as well.
"It's important to get three points off Man United, the same as it is against Reading," Laudrup said.
"But, being honest, I'd rather beat Villa here. Of course, we would like to win (against United), but it would put so much focus on the club at time where we need to focus on games.
"So if I knew we were going to get six or seven points in the next three games, I wouldn't mind losing it. Of course, it doesn't work like that and we will want to win the game.
"They are the number one club from the last 15 or 20 years in terms of titles, finals and a legendary manager -- but it is still only one game."
Swansea goalkeeper Michel Vorm could return after being sidelined since October with a groin injury.
Pablo Hernandez might feature against United after overcoming a thigh problem, but defender Angel Rangel is out with a calf injury.