6th-seeded Cilic fights off McDonald

Marin Cilic capped a 25-ace performance with a pair to serve out a second-round victory at the Australian Open, beating 81st-ranked Mackenzie McDonald of the U.S. 7-5, 6-7 (9), 6-4, 6-4.

Cilic was the runner-up here to Roger Federer last year and is seeded No. 6 this time.

Cilic hasn't lost at Melbourne Park to anyone ranked as low as McDonald since 2007.