London:The Liverpool-Chelsea Champions League odyssey enters its fifth chapter on Wednesday, with the English rivals preparing for a quarter-final match expected to be as tight as all their annual European duels since 2005.
Of those eight matches, the Premier League sides have played out four draws and won two apiece. Before Chelsea won last year's semi-final series, the previous six Liverpool-Chelsea meetings in European competition had produced just three goals.
The teams know each other so well that even Rafa Benitez, Liverpool's master tactician in Europe, will be struggling to produce a surprise element at Anfield.
Although praising Benitez as a "very smart manager," Chelsea's interim manager Guus Hiddink said there were no secrets in modern football.
"The players are known by the managers, the players know each other very well, the managers know how they play, so it's very, very tight," Hiddink said. "I'm looking forward to this battle, but in the end we can plan what we want - the players, they have to execute it and it always depends on those little details in the execution."
The only constant in recent years has been Benitez, who was in charge when Liverpool edged Chelsea in the semi-finals and then lifted the trophy in 2005 with a win over Milan.
Hiddink is Chelsea's fourth manager in that period. Unlike Jose Mourinho and Avram Grant, Luiz Felipe Scolari did not last until the end of the season to face Liverpool in Europe.
The big difference this season is the threat Liverpool is finally providing domestically, shifting Europe to second in Benitez' priority list. The Reds are just a point behind league-leading Manchester United and have completed a double for the first time since 1989-90 over third-place Chelsea -inspired by Fernando Torres and Steven Gerrard.
"This is probably the worst time to be facing Gerrard," said Chelsea captain John Terry, part of the team that lost last season's Champions League final to Manchester United.
"He's one of the best players in the world, that's for sure. He's in great form at the minute. I'm sort of dreading going there to play him because he is different class."
The one certainty is an English semifinalist for the sixth straight season. The mission facing FC Porto and Villarreal is to prevent another two Premier League clubs reach the semis.
"There could be three English teams in the semis again, that's how strong we are," Manchester United manager Alex Ferguson said ahead of Tuesday's home match against Porto.
"Because of the competitive nature of our Premier League I think an English team will win the Champions League again this year and it could be another all-English final."
History is against United winning, though, as European club champions since 1992 - when Champions League format began - have never managed to defend their title.
Portuguese league leader Porto will be drawing inspiration from their victorious trip to Old Trafford in 2004 en route winning the competition under Mourinho.
Arsenal and Villarreal meet in Spain on Tuesday.
Villarreal will be without star forward Santi Cazorla, who has been sidelined for the remainder of the season with a leg injury.
But his side is unbeaten at El Madrigal in European play, including the return leg of the 2006 semi-finals against Arsenal, which ended 0-0. Arsenal reached the final due to its first-leg goal, but lost in Paris to Barcelona.
Barcelona has been matched with Bayern Munich in the only quarter-final without an English side.
The Spanish leaders host Bayern - fourth in the Bundesliga - on Wednesday on the back of five straight La Liga victories.
While Samuel Eto'o scored his 26th goal of the season in Saturday's 1-0 win at Valladolid, coach Pep Guardiola will be looking to repair Barcelona's leaky Champions League defence against the German club.
Barcelona has conceded 11 goals - the most of any of the eight quarter-finalists and has yet to keep a clean sheet at the Camp Nou.