Alexis Galarneau and Gabriel Diallo got defending champion Canada rolling with a 2-0 victory in a tie against Italy to open the group stage of the Davis Cup Finals on Wednesday.Galarneau of Laval, Que., earned a 7-6 (8), 6-4 win over Lorenzo Sonego in the opening singles match. Montreal’s Diallo then defeated Lorenzo Musetti 7-5, 6-4 to clinch the win over the hosts.Diallo and Galarneau thus recorded their first career victories in the Davis Cup and their first career wins against a top-50 ATP ranked player. Musetti is the world No. 18, while Sonego is ranked 38th.”Feels amazing,” Diallo said after his match. “Especially the fact that Alexis brought the first point, which was crucial. Set the bar also really high for me to try and play some of my best tennis because obviously he played a great match.”I was in the locker room and was watching his match. It was so inspiring to watch, kind of got goosebumps and was really looking forward to hop on the court.”WATCH | Diallo helps Canada to 2-0 day against Italy at Davis Cup:Gabriel Diallo gives Canada win over Italy at Davis CupMontreal’s Gabriel Diallo defeated Italy’s Lorenzo Musetti 7-5, 6-4 in the second rubber match of the day breaking the tie with Italy, as Canada advances at the Davis Cup.Galarneau teamed up with Vasek Pospisil of Vernon, B.C., to win the doubles match, defeating Matteo Arnaldi and Simone Bolelli 6-7 (4), 6-4, 7-6 (3).Diallo, 21, hit 10 aces and had zero double faults in his one-hour 23-minute victory. He also broke on two of his three chances, while holding Musetti without a breakpoint opportunity.”I was really happy with the way I served, the way I played behind my serve as well and managed to get two crucial breaks and that was all I needed today to get the job done,” said Diallo, who is ranked 158th.The 24-year-old Galarneau was tested by Sonego from the very first game of the match, which he took eight minutes to win after saving four break points.Galarneau then regrouped and sealed the outcome of the first set by saving two set points during the tiebreak.”It was a roller-coaster set, even though I managed to avoid the low points,” Galarneau said of the first set. “I have to thank my teammates and my bench because they helped me not to dwell on it when things were a little tougher. It was a determining factor in my victory.”WATCH | Galarneau kickstarts Canada’s Davis Cup defence with upset over Sonego:Canada’s Alexis Galarneau upsets Italy’s Lorenzo Sonego in opening Davis Cup match200th world-ranked Alexis Galarneau of Laval, Que., took down world No. 38 Lorenzo Sonego 7-6(8), 6-4, to open Davis Cup play Wednesday in Bologna, Italy.Galarneau — the 200th-ranked player on the tour — continued his good work in the second set and gave himself a shot at victory by breaking in the fifth game to take a 3-2 lead. Sonego then called for a sports therapist as he appeared to be bothered by a right leg injury in the calf region.It didn’t shake the concentration of Galarneau, who confirmed his team’s victory by converting his first of two match points when serving at 5-4 — to the dismay of the mostly home crowd.”It was amazing,” Galarneau said following his match. “Amazing atmosphere, amazing time for me to win a Davis Cup tie.”I just had a lot of fun out there. Teammates were great, the crowd was going crazy. They weren’t for me but I still appreciate them coming out and the passion they showed was amazing.”WATCH | Pospisil, Galarneau complete sweep of Italy at Davis Cup:Canada’s Pospisil, Galarneau victorious at Davis Cup to complete sweep of ItalyCanadians Vasek Pospisil and Alexis Galarneau defeat Matteo Arnaldi and Simone Bolelli of Italy 6-7 (4), 6-4, 7-6 (3) in their doubles rubber at the Davis Cup Finals. Canada sweeps the tie against the Italians 3-0 to open their group stage.Canada is set to face Sweden on Thursday before wrapping up Group A play on Saturday against Chile.The top two teams from the four groups advance to the knockout stage which will take place Nov. 21-26 in Malaga, Spain.Canada won the Davis Cup last year for the first time since 1913.Denis Shapovalov, of Richmond Hill, Ont., is representing Canada for the ninth time in his career, but he was not called upon on Wednesday.Montreal’s Felix Auger-Aliassime, the 14th-ranked player in the world, is absent from the competition.U.S., Great Britain and Czech Republic also winThe United States, Great Britain and the Czech Republic also won on Wednesday.Australia opened with a 2-1 loss to Great Britain in their group in Manchester, England. The Australians lost both singles matches in three sets, with Thanasi Kokkinakis beaten by Jack Draper and Alex de Minaur defeated by Dan Evans, before a consolation victory in the doubles for Matthew Ebden and Max Purcell.The Americans opened their match in Split against host nation Croatia with a 6-4, 6-2 win for Mackenzie McDonald over Dino Prizmic only for 11th-ranked Frances Tiafoe to lose surprisingly to No. 77 Borna Gojo, 6-4, 7-6 (6).In the deciding doubles, Austin Krajicek and Rajeev Ram beat Ivan Dodig and Mate Pavic 7-6 (5), 6-7 (3), 6-2 to secure a 2-1 win for the U.S.The Czechs won 3-0 against Spain, which is without Wimbledon champion Carlos Alcaraz, in the Spanish city of Valencia.