With Lazio, Mancini won his second "scudetto" and Cup Winners' Cup titles, as well as two more Coppa Italias. In the 1999–00 season, Lazio won the "scudetto" and Coppa Italia, but Mancini failed to score in 20 matches and later announced his playing retirement. He joined Lazio's coaching staff as Sven-Göran Eriksson's number two. In 2011, when asked about Mancini, Eriksson said: "I took him to Lazio with me and he wanted to be a manager even while he was a player. He was the coach, he was the kit man, he was the bus driver, everything. At Sampdoria he wanted to check that everything was in place before training. Sometimes I would have to tell him: 'Mancio, you have a game to play on Sunday, you will be exhausted if you have to control everything.' But he was like that."