[citation needed] Following the 1998–99 season, during which he helped Vitesse to qualify for Europe, Westerveld was sold to Liverpool, where he succeeded David James.

[7] He was Gérard Houllier's first choice to succeed James as Anfield's number one, and Westerveld fully justified the manager's confidence by playing a leading role in Liverpool's return to Europe, conceding the fewest goals in the 1999–2000 Premier League season.

[citation needed] He played a key role in the treble season of 2000–01 for Liverpool, emerging as the hero of the League Cup final victory over Birmingham City, making the winning save from Andrew Johnson in the penalty shoot-out.

After a major mistake in a match against Bolton Wanderers on 27 August 2001, he was put on the bench by Houllier, who promptly signed two new goalkeepers, Jerzy Dudek and Chris Kirkland.

However, after an inconsistent time at Fratton Park, in which he played only six league matches, he was allowed to move on a 28-day loan to Everton, rivals of his former club Liverpool, on 24 February 2006.

[11] Everton had a temporary goalkeeping crisis in which Nigel Martyn, Richard Wright and Iain Turner were all unavailable, and Westerveld played two matches for them.