Manchester United manager Sir Alex Ferguson has claimed Chelsea bought Fernando Torres because they are "obsessed" with winning the Champions League.
The Blues, who trail United 1-0 ahead of Tuesday's quarter-final second leg, paid Liverpool £50m for Torres at the end of the January transfer window.
"It seems to be an obsession to win the European Cup and that's why they bought Torres," said Ferguson.
"[Chelsea owner Roman] Abramovich has nailed his colours to the mast."
Wayne Rooney's first-half goal at Stamford Bridge proved the difference between the sides in last week's first leg, while Torres is still searching for his first goal since joining the club.
Chelsea must win at Old Trafford to stand a chance of progressing to the last four.
"At the end of the day it's a very difficult competition to win, all the best teams are there," Ferguson added.
"You see the form of Barcelona at the moment - it's fantastic. It looks like it will be Barcelona-Real Madrid in the semi-final. If we are [playing] on different days, I'll be going to that."
Ferguson said he understood Chelsea's preoccupation with winning Europe's premier club competition for the first time.
The Scot ended United's 31-year wait for a second European Cup by beating Bayern Munich 2-1 in the 1999 final in Barcelona.
United collected their third crown after beating Chelsea on penalties in the 2008 final.
"If you are obsessed with winning the European Cup you are stretching yourself a bit, but I can understand it," Ferguson said.
"When we did it in Barcelona it was the greatest feeling of all time and it took the monkey off my back.
"But it doesn't mean Chelsea will be any more desperate than Manchester United to win tomorrow night."
The Blues, who trail United 1-0 ahead of Tuesday's quarter-final second leg, paid Liverpool £50m for Torres at the end of the January transfer window.
"It seems to be an obsession to win the European Cup and that's why they bought Torres," said Ferguson.
"[Chelsea owner Roman] Abramovich has nailed his colours to the mast."
Wayne Rooney's first-half goal at Stamford Bridge proved the difference between the sides in last week's first leg, while Torres is still searching for his first goal since joining the club.
Chelsea must win at Old Trafford to stand a chance of progressing to the last four.
"At the end of the day it's a very difficult competition to win, all the best teams are there," Ferguson added.
"You see the form of Barcelona at the moment - it's fantastic. It looks like it will be Barcelona-Real Madrid in the semi-final. If we are [playing] on different days, I'll be going to that."
Ferguson said he understood Chelsea's preoccupation with winning Europe's premier club competition for the first time.
The Scot ended United's 31-year wait for a second European Cup by beating Bayern Munich 2-1 in the 1999 final in Barcelona.
United collected their third crown after beating Chelsea on penalties in the 2008 final.
"If you are obsessed with winning the European Cup you are stretching yourself a bit, but I can understand it," Ferguson said.
"When we did it in Barcelona it was the greatest feeling of all time and it took the monkey off my back.
"But it doesn't mean Chelsea will be any more desperate than Manchester United to win tomorrow night."
