Guus Hiddink says Bolton's fightback was a wake-up call at the right time for Chelsea as they look to see off Liverpool's Champions League bid.Chelsea lead 3-1 on aggregate after their stunning win at Anfield in midweek and Liverpool need at least three goals to have any chance turning the tie around in their favour and reaching the semi-finals.So Chelsea's dramatic collapse against Bolton on Saturday at Stamford Bridge will have given Rafa Benitez's Reds much encouragement.Chelsea were 4-0 in front with just 20 minutes remaining thanks to a brace from Didier Drogba, a Frank Lampard penalty and Michael Ballack's first league goal of the season.But Hiddink substituted Lampard and Drogba in the 65th minute and Chelsea then capitulated as Bolton scored three goals in nine amazing minutes through Andrew O'Brien (71), Chris Basham (74) and Matt Taylor (80).And it required a clearance off the line by Deco in the final seconds to ensure Chelsea took all three points and remained in the title hunt."It was a wake-up call for us and we talked to the boys straight after the game," said Hiddink. "If you play at the top, you cannot afford to do it twice."We must not let it happen again. It is normal that the players react to the situation."It was a typical English game. We were leading 4-0 with 20 minutes to go and waiting for a fifth."All of a sudden we got very sloppy and too relaxed and didn't win any duels defensively."I am not just talking about the defence but also the midfield and front players. We conceded three goals in nine minutes I think - that should not be possible against a team that is near the top of the table."We did not perform well. There was a sequence of errors that we made."I don't think the substitutions were the cause. We were just too relaxed in the last 20 minutes."Bolton boss Gary Megson was not sure if his side's amazing fightback will give Liverpool more hope for Tuesday's quarter-final return leg against Chelsea, but he was full of praise for his players."It has given us great heart, which is the important thing," said Megson. "We'll probably get more credit for losing 4-3 at Chelsea than we did for winning 4-1 against Middlesbrough last week."We went through the whole range of emotions. There was anger at times with the way we defended but for the first 25 minutes we looked quite secure."For the last 25 minutes we bossed the game and scored three goals. I think we are the only team to come to Stamford Bridge and do that this season and yet we still lost 4-3 which is where the disappointment comes in."The introduction of young Chris Basham was more to do with the fightback. Because he is a youngster and has never played at Stamford Bridge before, he gave us the enthusiasm, the desire, the drive and the tenacity to go and have a real good go."That got an extra 10% out of everybody else. At 4-1 it is no big deal, at 4-2 you have got a little bit of momentum and at 4-3 you saw what was happening. We had one kicked off the line at the end but Chelsea are a quality side."As much as we are pleased to come and score three goals to give away four to a team like Chelsea, you are not going to pick up too many points."