Harry Redknapp felt Tottenham had been left with an "impossible task" against Real Madrid after losing Peter Crouch to an early red card.
Spurs were already trailing to an Emmanuel Adebayor header when Crouch was dismissed in the 15th minute for the second of two bookings, and hosts Madrid took full advantage to claim a 4-0 first-leg victory at the Bernabeu on Tuesday night and make a huge stride towards the semi-finals of the Champions League.
Spurs, who saw Aaron Lennon pull out just prior to kick-off because of illness, managed to keep Madrid to just a one-goal advantage by half-time, but Jose Mourinho's men took the match away from the visitors with three second-half goals from former Arsenal striker Adebayor, Angel Di Maria and Cristiano Ronaldo.
Redknapp admitted: "It was a difficult night. I lost Aaron Lennon just as the team were walking onto the pitch, he didn't feel well enough to play so we had to change that straight away, and obviously to go down to 10 men is difficult, you need a miracle here to win with 10 men.
"Better teams than us would probably have struggled tonight. It was an uphill task, an impossible task. For the first half I thought we did fantastic with 10 men, we had a couple of good opportunities on the break but we ran out of steam, with Gareth (Bale) cramping up, and we lost our right back (Vedran Corluka). It was one of those nights.
"Obviously we're disappointed. What do you do about the third goal? An unbelievable finish, they've got quality players and you need to have 11 to have any chance and be at your best here."
Crouch picked up his first caution in the eighth minute for a foul on Sergio Ramos and then seven minutes later got his marching orders following a late challenge on Marcelo near the Madrid box.
Redknapp said of the England striker's dismissal: "I haven't spoken to Crouchy to be honest, I'm disappointed obviously, it's all we needed to go down to 10 men so early in the game."
The loss means Spurs need to create a huge upset to avoid tumbling out of the competition in the second leg at White Hart Lane, but while Redknapp knows the odds are stacked against them, he is refusing to concede the tie is definitely over.
"Well, it's going to be very difficult. It certainly couldn't be much more difficult than being 4-0 down to Real Madrid, but we're at home, we'll give it a go," said Redknapp, whose side gave Inter Milan a huge scare in the group stages after trailing 4-0 at half-time at the San Siro by pulling back three second-half goals.
"It's never over until it's over and you never know, though obviously we've got a mountain to climb, there's no doubt about that.
"I knew it would be a difficult night here but to come here and lose a player after 10 minutes made it impossible for us really.
"It was a case then of trying to hold on, even at 2-0 I thought 'let's get out of here with 2-0 and we've done a miracle', but we ran out of legs in the end. We ended up with people out there who were struggling, so it was difficult.
"But we've done fantastic (in the Champions League), it's been a great experience so far, and there's still a game to come at White Hart Lane."
Redknapp added of Crouch's dismissal: "I haven't seen a replay of the tackle, the referee made the decision and I'm sure he made what he thought was the right decision.
"I haven't seen it but he (Crouch) shouldn't have taken the chance, he's already got a yellow card, he shouldn't take the chance that he might get a red card, so that's disappointing."
Madrid, who are playing in the quarter-finals for the first time since 2004 after six successive years of being dumped out at the last-16 stage, are now overwhelming favourites to progress through to a semi-final showdown with either arch-rivals Barcelona or Shakhtar Donetsk.
However, Mourinho refused to concede his side's place in the last four had been secured by Tuesday night's thrashing.
"We're not in the semis, last time that Real Madrid played in the quarters we also won at home, 4-2 I think (against Monaco), and then we were out," said Mourinho, who is looking to become the first coach to conquer Europe with three different clubs.
"In the second-leg match in England, anything is possible, we have to respect this high-quality opponent and we have to go there and play a serious match and try to get through to the next level."
Asked if he had any sympathy for his old friend Redknapp after Spurs were reduced to 10 men so early on, Mourinho added: "I feel complete sympathy. I have good experience of playing with 10 men in the Champions league, I know how difficult it is.
"You just have to defend, if you've got an advantage you defend, defend and defend. And if you are already losing and you have to attack, it's an impossible job and I think they will try everything in the second leg.
"They are top people, they have belief. It's not an easy place to play and they will fight for sure."
