MELBOURNE—Fifth-seeded Aryna Sabalenka defeated Belinda Bencic, 7-5, 6-2, on Monday to reach the quarterfinals of the Australian Open for the first time. Bencic double-faulted to drop the first set, which put Sabalenka in control from that point. No. 4-seeded Caroline Garcia faced Magda Linette later Monday for another place in…