Chelsea dipped into their reserves again last night but this time they came up empty-handed. Wimbledon, not for the first time, showed the greater spirit and were rewarded with their third semi-final appearance in three seasons.
The holders began on the back foot with five men strung across midfield, but the plan backfired and, despite a rousing finish, Chelsea played too indifferently for too long to avoid their first defeat in 19 games, one match short of a club record.
Chelsea player-manager Gianluca Vialli was big enough to admit his error. "I probably confused the players with five in midfield and just myself up front," he said. "I made a tactical mistake. We won't play that way again."
But this must not detract from Wimbledon's achievement as they go into tonight's semi-final draw with the chance to make up for defeats at this stage of this competition and the FA Cup two seasons ago. Fans are again dusting down memories of their famous Wembley win in 1988.
Joe Kinnear's perennial underdogs got off to a great start last night, going ahead after 19 minutes. Neil Ardley swung in a free-kick, Dmitri Kharine and his defenders appeared frozen to the spot by the bitter night air, and Robbie Earle scored with the easiest of headers from six yards.
The goal was just reward for Wimbledon's more tenacious attitude as they made light of Chelsea's attempt to boss midfield with numbers by simply bringing Ardley inside to even the odds. Three minutes after taking the lead, Wimbledon nearly extended it as Frank Leboeuf under-hit a back-pass, but Carl Leaburn shot wide.
After fine wins against under-strength Aston Villa and Arsenal sides in the previous rounds, Chelsea's habit of fielding predominantly second squad players in this tournament was being exposed by a full-strength Wimbledon.
Not even the return of Dennis Wise after a four-game ban could lift the first-half lethargy of a Chelsea team showing seven changes from last Saturday's draw with Sheffield Wednesday. In psychological terms their 3-0 win over Wimbledon a fortnight ago meant little.
Vialli was a striker alone as much as a lone striker as his midfield struggled to establish communication with him, and Chelsea's all-white strip took on the appearance of a collective flag of surrender.
Vialli's response was to give himself a striking partner, bringing on Tore Andre Flo, and for the first time in the game Chelsea soon went close to scoring. Gustavo Poyet missed narrowly from 18 yards, then headed straight at the goalkeeper.
Wimbledon, however, continued to pose a threat. On 51 minutes Michael Hughes fired in a stinging shot which Kharine failed to hold and then had to scramble away with his feet.
And 15 minutes from time they doubled their lead. Leboeuf brought down Gayle as they tussled for the ball in the area and referee Graham Poll had no hesitation in pointing to the spot.
An uncomplaining Leboeuf was booked for his troubles before Hughes stepped up to hammer home the penalty after 74 minutes.
Stung by the depth of their predicament Chelsea upped a gear. Four minutes from time a goal finally came as Vialli turned in Flo's cross from close range for his sixth goal in three ties in this competition.
In injury-time the substitute Albert Ferrer was presented with a wonderful opportunity to force extra-time but, after finding himself free on the right of the area, he slammed the ball into the side-netting.
Wimbledon: Sullivan, Cunningham, Perry, Blackwell, Thatcher, Earle, Gayle, Ardley, Leaburn (Ekoku 73), Hughes, Euell. Subs Not Used: Kimble, Roberts, Heald, Kennedy. Booked: Earle, Hughes, Euell, Gayle. Goals: Earle 20, Hughes 75 pen.
Chelsea: Kharine, Petrescu, Babayaro, Leboeuf, Goldbaek (Flo 46), Poyet, Vialli, Wise, Duberry (Ferrer 78), Lambourde, Morris (Di Matteo 70). Subs Not Used: Hitchcock, Nicholls. Booked: Leboeuf. Goal: Vialli 85.