MELBOURNE (Reuters) - Novak Djokovic kicked off his 2021 season in style on his favourite Rod Laver Arena court with a clinical 7-5 7-5 win over Canadian talent Denis Shapovalov in the ATP Cup on Tuesday. Leading Serbia’s title defence in the team-based event, Djokovic was thrilled with his form in the Group A clash, a rematch of last year’s quarter-final against Shapovalov. “It’s a great opening of the season. I hope all of you who came here enjoyed it because I certainly did,” the world number one told a small crowd at the stadium, soaking up boisterous cheers from Serbian fans. Last year the Canadian had pushed Djokovic to a third-set tiebreak but the Serb wrapped things up more quickly on Tuesday, breaking Shapovalov as he served to stay in the match. Himself unbroken on serve, Djokovic sealed the match with a sparkling winner, scrambling to his right to whip a curling forehand passing shot down the line. The win levelled the tie at 1-1 after Canada’s Milos Raonic had eased past Dusan Lajovic 6-3 6-4. Djokovic, who will bid for a record-extending ninth Australian Open title, will play in the decisive doubles as he looks to extend his unbeaten record in the ATP Cup to 10 matches. While Djokovic enjoyed a dream start, Austria’s world number three Dominic Thiem slumped to a 6-2 6-4 defeat to Italy’s Matteo Berrettini in his opener. Blasting groundstrokes metres past the baseline, the U.S. Open champion was broken four times in a rusty display at John Cain Arena as Berrettini dominated the clash of hard-hitters. Thiem rallied in the second set to break Berrettini for the first time but surrendered the match the way he played it, with a big swing at a backhand that thudded into the net. Having pushed Djokovic to five sets in the Australian Open final last year, Thiem is among the top contenders looking to dethrone the Serb at the Feb. 8-21 Grand Slam. Berrettini was ecstatic to take down Thiem in the Group C tie and put Italy back on level terms with Austria at 1-1 after Dennis Novak romped past Fabio Fognini 6-3 6-2 in the morning. “I’m really happy for my performance,” Berrettini said on court. “Playing for your country is something special.” France, the other Group C team, start their tournament against Italy on Wednesday. The winning nations of the four groups advance to the semi-finals.