After Tuesday's 11-goal fireworks the matches are likely to be tighter in Wednesday's Champions League quarter-final first legs as Chelsea entertain Manchester United and Barcelona host Shakhtar Donetsk.

The all-English clash at Stamford Bridge is a repeat of the 2008 final won by United on penalties and just two of their last 11 competitive meetings have been decided by more than one goal.

Having seen Tottenham Hotspur crushed 4-0 at Real Madrid on Tuesday it looks likely the winner of the Chelsea-United tie will be the only remaining English side in the competition with the final due to be held at Wembley on May 28.

United, leading the Premier League and into the semi-finals of the FA Cup, are still dreaming of repeating their 1999 treble but the Champions League remains the only realistic hope of silverware for last year's domestic double winners Chelsea.

Schalke 04's stunning 5-2 victory at holders Inter Milan on Tuesday will have given encouragement to Shakhtar's players and fans as they prepare to face the favourites at the Nou Camp.

The Brazilian-packed Ukraine side are in the last eight for the first time and although they must perform at their peak they can draw inspiration from their group stage win in Barcelona in December 2008, the season the Spaniards went on to take the title.

Pep Guardiola struck a starkly downbeat note on Tuesday when he warned euphoric Barcelona fans against underestimating their team's Champions League quarter-final opponents Shakhtar Donetsk.

Guardiola's side are on course for a treble as they lead La Liga, have a King's Cup final in two weeks' time and are one of the favourites in Europe's elite club competition.

"There isn't much talk about Shakhtar and they say the league is won," Guardiola told a news conference ahead of the first leg at the Nou Camp.

"The sensations I have aren't good."

The Ukrainians, who are in the quarter-finals for the first time, had one of the best records in the group stage.

They ran Barca close in the Europea Super Cup in 2009 and stole a 3-2 win at the Nou Camp the last time they met in the Champions League group stages late in 2008.

"We have to play a good game or the tie will get complicated," Guardiola added.

"I've told the players we have to be focused because it would be dangerous to have to settle the tie over there.

"They are a great team, a super team that is very aggressive. They defend very well and they work like animals. They finished above Arsenal in their group."

Shakhtar coach Mircea Lucescu told an earlier news conference he believed the current Barca side were "the best team in the history of football" but noted that his club had developed rapidly in recent seasons.

"Shakhtar is the team that has progressed the most," the Romanian said.

"We won the UEFA Cup a few years ago (2009) against a great club like Werder Bremen and now we are trying to consolidate in the Champions League," he added.

Barcelona forward Lionel Messi is struggling with a leg injury as the 2009 winners prepare to host Shakhtar Donetsk in their Champions League quarter-final first leg on Wednesday.

The Argentine World Player of the Year, joint top scorer in this season's competition with eight goals, had an injury scare on international duty and was only used as a substitute in the 1-0 La Liga win at Villarreal on Saturday.

"In Villarreal I did not feel good," Messi told a news conference on Tuesday at Barca's Nou Camp stadium.

"I'll work as hard as possible so that the discomfort disappears and little by little I feel better."

Messi warned against underestimating Ukraine's Shakhtar, who shocked Barca 3-2 at the Nou Camp in the group stage in December 2008. They also pushed the Catalan club all the way in the European Super Cup in 2009, eventually losing 1-0 to a Pedro strike in extra time.

"We know it will be a very tough game as we are facing a team that has some great players and that knows how to play very good football," Messi said.

"Matches against Shakhtar are always very close," he added. "You just have to look at the result in the European Super Cup and the last few games we have played them.

"We'll have to go out there very focused as otherwise they could surprise us."