They set up the possibility of a dream ending thanks to wins in the semifinals of the English FA Cup.
Four days after United's 7-1 demolition of Roma in the UEFA Champions League -- arguably the most outstanding performance by a team on the European stage since the competition's new format was introduced in 1992 -- United put on another attacking show, beating plucky Watford, 4-1, with two goals by Wayne Rooney and one by Cristiano Ronaldo and Kieran Richardson.
On Sunday, Chelsea had to work to defeat Blackburn Rover, 2-1, in overtime thanks to Michael Ballack's goal. Chelsea was the last team to win the FA Cup at the old Wembley in 2000, and Manager Jose Mourinho heads to the new stadium on May 19 aiming for his first victory in the competition and still on course for an unprecedented quadruple.
The Blues have already won the League Cup, while Chelsea and United are still alive in the Premier League and Champions League as well as the FA Cup. United leads Chelsea by three points in the EPL; they meet on May 9 at Chelsea's Stamford Bridge in a makeup game, four days before the season finale. United and Chelsea are through to the semifinals of the Champions League, which concludes with the final on May 23 in Athens.
Mourinho says what his club and United have accomplished is amazing.
"It would be great to play them three times between now and the end of the season," Mourinho said after the Blackburn game. "The reality is what Chelsea and Manchester United are doing this season is unbelievable."
Mourinho was full of praise for Blackburn, which could have won the game late in regulation but Norwegian Morten Gamst Pedersen's shot hit the post.
"It's a very special feeling, I think the game was amazing," Mourinho said. "It was the kind of game where you win you are crazy with happiness but you have a lot of thoughts for your opponents. They gave us a game -- it was not a surprise to me I was waiting for this -- they fought like heroes."