There were 54 of each against Halep: a statistic unlikely to startle those who had watched Ostapenko slug and shrug her way through the six matches leading to the final.“At some points, I was like a spectator on the court,” Halep said.Ostapenko set the tone from the first rally on Saturday, winning it with a big backhand down the line that Halep could not handle. She broke Halep at love in that opening game with a bolt of a backhand winner down the line.Though Ostapenko would have plenty of wobbles and misfires in the taut moments to come, she never once gave the impression that she was out of her element.After rallying from deficits of 0-3 in the second set and 1-3 in the third, she finished the way she had started: nervelessly nailing a backhand return winner down the line, to complete one of the most unexpected title runs in tennis’s long history.“I mean, I think I cannot believe I am Roland Garros champion, and I am only 20 years old,” Ostapenko said.She turned 20 during the tournament and was still a teenager when she lost the first set of her first-round match against Louisa Chirico of the United States. But Ostapenko rallied, as she would against two much more experienced players — the 2011  champion Sam Stosur in the fourth round, and the former world No. 1 Caroline Wozniacki in the quarterfinals.Add Halep to the list. Despite her 3-1 lead in the third set on Saturday, she could not hold off Ostapenko, whose power comes from her sturdy lower body, exquisite timing and lightning-quick racket-head speed.