Lazio overcame a sixth-minute red card to defeat Rosenborg 3-1 in Group G of the Europa League.
The Italians were facing an uphill challenge when Mauricio was dismissed early on, but they converted the few chances that came their way, claiming a 2-0 lead inside 54 minutes through Alessandro Matri and Felipe Anderson.
Alexander Soderlund pulled one back with 21 minutes to go but Antonio Candreva restored the two-goal cushion late on with a followed-up finish after his penalty had been saved.
West Brom have completed the signings of Cristian Gamboa from Rosenborg and Jason Davidson from Heracles Almelo for undisclosed fees.
Gamboa arrives at the Baggies after having his work permit application approved by a Football Association appeal panel and has signed a three-year contract.
The 24-year-old, who started all five of Costa Rica's World Cup matches this summer, will join up with his new teammates once he has received his visa and passport.