Vengeance (2001) was the first Vengeance professional wrestling pay-per-view (PPV) event produced by the World Wrestling Federation (WWF). It was presented by Lugz and took place on December 9, 2001, at the San Diego Sports Arena in San Diego, California, and it was the only event under the Vengeance banner to take place in December, replacing WWE's former December PPV, Armageddon.

The main feature of the event was a three-match tournament to unify the WWF Championship and the World Championship (formerly the WCW World Heavyweight Championship) into what became known as the Undisputed WWF Championship.

This was the final WWF PPV to air on Channel 4 in the United Kingdom.

The Invasion, which began in June 2001, ended at Survivor Series, the previous event, when Team WWF won a "Winner Takes All" Survivor Series match. The Alliance was forced to close business as a result, and all their titles except for the World Championship were abandoned (the remaining championships were unified with their respective WWF equivalents and subsequently deactivated, and the WCW Cruiserweight Championship became a WWF title). On Raw the following night, WWF Owner Vince McMahon attempted to strip Stone Cold Steve Austin, who was a member of The Alliance, of his WWF Championship, and award it to Kurt Angle due to his actions in costing The Alliance the match. However, before he could do so Ric Flair, who had not been seen on any wrestling program since McMahon's purchase of WCW in March 2001, came out and announced that the leaders of The Alliance, Shane and Stephanie McMahon, had sold their stake in the WWF to him and that he was now equal partners with McMahon. Austin then attacked both Angle and McMahon, after which Flair presented him with his title belt.

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