World No. 1 Djokovic took a tumble on a breakpoint in the first game, rallied from a breakdown, found his rhythm from the baseline to fire 23 winners to secure victory after 90 minutes.
Ruud converted the lone breakpoint in the first set as he took Djokovic to the tiebreak. But that was his only success in the match as the Serb World No 1 did not give him many chances, converting three of the five break points her earned in the match.
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"I recovered from that fall on that breakpoint in that first game," Djokovic said in his on-court interview as reported by the ATP. "It was very strange. I played a good forehand and came into the net and had a pretty comfortable overhead and I slipped, tripped, dropped my racquet, and lost my serve. The conditions here are quite tough. If you lose your serve, it is difficult to get it back. But I managed to stay in. I am very pleased with the way I handled the match."
Djokovic served 10 aces as compared to none by Ruud, who also sent down four double faults. He won 90% first server points and won a total of 77% total service points.
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The Serbian, who last lifted the Brad Drewett Trophy in 2015, is aiming to tie Roge' Federer's record six triumphs at the tournament, which is being held in Turin for the first time. Djokovic will also play Stefanos Tsitsipasof Greece and Andrey Rublev of Russia in the round-robin stage, with the pair facing off in their opening match on Monday evening.