Liverpool against Chelsea is the most eagerly anticipated Champions League quarter-final first leg this week despite the pair having met in the competition in each of the last four seasons.
Liverpool's stunning form at home and abroad and Chelsea's resurgence under interim coach Guus Hiddink make for an intriguing all-English tie rather than a boring fifth instalment of what has usually been a cagey affair.
Rafa Benitez's side, who beat Real Madrid home and away in the last round and also humbled Manchester United recently to reopen the Premier League title race, have home advantage on Wednesday with the return leg in London on April 14.
"There are no secrets in modern football," Hiddink told uefa.com before his team beat Newcastle United 2-0 on Saturday and Liverpool won 1-0 at Fulham with a last-gasp goal.
"The players are known by the managers, the players know each other very well, the managers know how they play, so it's very open and very tight. Benitez has proven he is a very smart manager. I'm looking forward to this battle."
Familiarity is a theme across the ties with holders Manchester United hosting Porto on Tuesday, five years after the Portuguese club knocked out Alex Ferguson's side on their way to winning the 2004 Champions League.
United have had a wobble domestically since eliminating Inter Milan in the last 16 but overcame Aston Villa 3-2 in a thriller on Sunday thanks to a stoppage-time winner.
Striker Dimitar Berbatov misses out with an ankle injury.
Also on Tuesday, Villarreal host Arsenal with the Spanish club's winger Robert Pires coming up against his former team.
"When I go out to face Arsenal for the first time since leaving, there will be a lot of emotion," he said. "But I'm sorry Arsenal fans, if I can play well and eliminate them then I'm going to do it. But for Villarreal, not for me."
Villarreal, without injured winger Santi Cazorla, want revenge after losing to Arsene Wenger's side in the 2006 last four before Arsenal were beaten by Barcelona in the final.
Spanish league leaders Barca entertain fellow heavyweights Bayern Munich on Wednesday in the only tie without English interest.
Bayern are reeling from a 5-1 thrashing by Wolfsburg on Saturday which dented their hopes of retaining the German title.
They will look to Franck Ribery to restore their confidence by outshining fellow magician Lionel Messi at the Nou Camp.
Liverpool captain Steven Gerrard, joint top scorer in the Champions League this term, is equally on fire and will have to be at his best to help beat a side he once almost joined.
He has already given the club a boost ahead of the tie by joining coach Benitez and Dirk Kuyt in signing a new contract.
Liverpool beat Chelsea in the 2005 and 2007 semi-finals while they drew 0-0 twice in the 2005/06 group stage. The Londoners finally overcame their bogey team in extra-time in last season's semi-final before losing to United in the final.