I blew it, admits Ranieri

Monaco 3 Chelsea 1

The Chelsea boss accepted his share of responsibility for the substitutions which backfired with the semi-final first leg seemingly in his team's hands.

With Monaco reduced to 10 men, and 37 minutes left, the self-confessed 'Tinkerman' replaced right-back Mario Melchiot with a third striker in Jimmy-Floyd Hasselbaink and went for victory.

However, Monaco responded by punishing Chelsea for their adventure on the counter-attack and Fernando Morientes and substitute Shabani Nonda completed a 3-1 first-leg victory.

Ranieri admitted: "With one player more, we wanted to win the match but we lost the plot in the last 15 minutes.

"The players all wanted to do something but in the wrong way as they ran with the ball rather than playing to our three strikers.

"But I would never fault the players. It's my fault. I accept this as I have been in football for 30 years.

"I made the changes because I was sure it was the best thing for the team."

Ranieri admitted Chelsea, for whom Hernan Crespo had equalised a Dado Prso first-half header, now have merely a "20 per cent" chance of reaching the final.

However, he made no comment on allegations of play-acting against Claude Makelele for his part in Andreas Zikos' dismissal.

And he was similarly unforthcoming amid television evidence that could lead to a UEFA investigation of Marcel Desailly for an apparent elbow on Morientes.

"I didn't see what happened," insisted Ranieri.

"Of course, I don't feel good now but Monaco played well and deserved to win."

Chelsea now need to win 2-0 at Stamford Bridge to make it through to the final and, while hope is not altogether lost, their recent record at home is none too impressive.

Indeed, they have stumbled ever since their quarter-final victory against Arsenal, with goalless draws against both Middlesbrough and Everton at home.

They made another unconvincing start in the Louis II stadium, with Monaco seizing the lead after just 16 minutes.

Melchiot was late with a tackle on Jerome Rothen and the winger exacted full punishment as he swung over the free-kick from which Monaco seized the lead.

Crespo tried to clear but the ball instead carried to the far post, where Prso sent a looping header past Marco Ambrosio into the far corner.

Chelsea took just five minutes to respond as Frank Lampard delivered an incisive cross which found three team-mates unmarked after questionably beating the offside trap.

Parker and Eidur Gudjohnsen combined to scramble the ball sideways to the lurking Crespo, who pounced as he turned and beat keeper Flavio Roma from point-blank range.

Now Chelsea were fully re-energised as Lampard shot wide and then crossed for Crespo to stab the ball over.

Ranieri's side still had to be cautious, with their defence remaining uncertain and the dangerous Ludovic Giuly beating Terry for pace before forcing Ambrosio into a neat save.

Lampard was at least orchestrating Chelsea's midfield with assuranceand poise, but the danger remainedas Gael Givet headed just over.

Ranieri cannot resist a half-time change, however, and the ineffective Jesper Gronkjaer was replaced by Juan Sebastian Veron.

That, however, only succeeded in inviting Monaco to attack, with Ambrosio beating away Prso's header, while Marcel Desailly headed off the line from Morientes.

Then came the moment that should have stacked the odds in Chelsea's favour, when Andreas Zikos went down under a challenge from Makelele and responded by pushing the Frenchman away. Makelele completely over-reacted and dived to the ground in supposed pain clutching his head, and referee Urs Meier caused uproar among the home fans by sending the Monaco midfielder off.

While Monaco hastily re-organised, Ranieri indulged in a frantic spell of tinkering as he upped the ante in bringing on Hasselbaink and taking off first Melchiot and then Parker.

Gudjohnsen twice came close, while Hasselbaink and Huth also threatened, but Chelsea had over-extended themselves.

First Morientes strode clear and buried his shot past Ambrosio and then, with seven minutes left, the stand-in Chelsea keeper was all too easily beaten by Nonda as well.

The gamble had been lost. Ranieri and his side can still redeem themselves in the return fixture but the Italian's future has never seemed more uncertain.

Monaco subs: Giuly (Nonda 83), Prso (Cisse 57), Rothen (Plasil 89).

Chelsea subs: Melchiot (Hasselbaink 62), Parker (Huth 69), Gronkjaer (Veron 46).