Arsenal manager Arsene Wenger again used the competition to give his squad players rare starts but they showed plenty of class as Eduardo da Silva's double gave them a 3-2 extra time win at Blackburn Rovers. Tottenham, steadily improving under coach Juande Ramos, had makeshift central defender Didier Zakora sent off after 20 minutes but were comfortable 2-0 winners over Manchester City. The two London clubs joined Everton in the last four after their victory over West Ham United last week, while Chelsea and Liverpool meet on Wednesday.
Arsenal, who beat Tottenham in the semi-finals last season before losing to Chelsea in the final, outclassed Rovers in the first half with Abou Diaby and Eduardo putting them 2-0 up inside half an hour.
Roque Santa Cruz pulled a goal back for Rovers on the stroke of halftime and he took his tally to five in two games with a 60th-minute header to make it 2-2.
Arsenal had Brazilian midfielder Denilson sent off for a rash challenge on David Dunn near the end of normal time as tempers flared.
Croatia international Eduardo showed his class in the first period of extra time, striding on to a defence-splitting pass from Alexandre Song and shooting low past Brad Friedel.
Striker Jermain Defoe gave Tottenham a fifth-minute at the City of Manchester Stadium, tapping in an Aaron Lennon cross, but the visitors were reduced to 10 men when Zakora was harshly shown a red card for sliding in on Elano.
Midfielder Steed Malbranque sealed victory for Spurs after a swift counter-attack eight minutes from time against a City side who have won 10 out of 10 home games in the Premier League this season.