MELBOURNE, Australia—Rafael Nadal finally got the better of a crazy, long tiebreaker and knew he’d won half the battle. After saving four set points and missing with the first six of his own, Nadal finally clinched a tiebreaker that lasted 28 minutes and 40 seconds to set himself on course to secure a spot in the Australian Open quarterfinals for a 14th time. After his 7–6 (14), 6–2, 6–2 fourth-round victory over fellow left-hander Adrian Mannarino on Sunday, Nadal is potentially just three wins away from a men’s record 21st Grand Slam singles title. He later reflected on a tiebreaker where momentum swung wildly; where chants of “Let’s go Rafa, Let’s go!” rang out; where a point was decided on a 25-shot rally with both players scrambling at full stretch; and that ended only when Nadal volleyed from deep in the court, and Mannarino’s reflex reply skewed wide. “Well, you …