López remained with Valencia for five years, helping the team to the final of the UEFA Champions League in the 1999–2000 season, when he was transferred to Lazio of Serie A for €35 million. During the first half of his spell in Italy's capital, he was partnered with compatriot Hernán Crespo in the front-line. However, López suffered from injury problems during his time at Lazio. During the 2000–2001 UEFA Champions League, he scored an direct goal from a corner kick against Anderlecht in the Stadio Olimpico.