The Barclays Premier League leaders face a stern test of their credentials as they travel to Stamford Bridge to face Andre Villas-Boas' side on Monday night
The Londoners may have dropped out of the top four due to other results over the weekend, but they have emerged from a difficult spell over the past week with 3-0 victories over Newcastle and Valencia.
Mancini said: "Last year Chelsea had a big lead over (Manchester) United but in the end United won the title by seven or eight points plus (nine).
"The Barclays Premier League is very difficult and in these two months, all the teams that play every three days will find it difficult.
"I think they can win it. They have 10 points less than us but we play two times against them and there are 24 games until the end of the season."