NEW YORK — Novak Djokovic and defending champion Marin Cilic took different routes into the fourth round of the U.S. Open while pressure mounted on Serena Williams' quest for a calendar grand slam on Friday.
After two routine wins to open the year's final slam, Williams was given a major fright by Bethanie Mattek-Sands before the 33-year-old American recovered for a 3-6 7-5 6-0 victory.
The 21-times grand slam singles winner, who is aiming to join Maureen Connolly (1953), Margaret Court (1970) and Steffi Graf (1988) as the only women to sweep the four grand slams in a single season, next faces fellow American Madison Keys.