Numbers ones Nadal and Pliskova hunt second round wins

Pliskova, who needed just 78 minutes to breeze past Poland's Magda Linette 6-2 6-1 in her opener will be eager to make similarly quick work of American qualifier Nicole Gibbs.

The Czech, however, will have to be wary of the 127th ranked Gibbs, who made the third round of the Australian Open before falling to eventual champion Serena Williams.

Nadal needed a tight first set to get in gear in his opening match then raced past Serb Dusan Lajovic 7-6 (6) 6-2 6-2 and will be well rested for his meeting with Japan's Taro Daniel.

The 121st ranked Daniel, who was born in the United States and lives in Spain, was involved in a five-set marathon against American Tommy Paul on Wednesday in match that was pushed back after rain wiped out play on Tuesday. Five-time US champion Roger Federer also survived a five-set nailbiter against hard-hitting American Frances Tiafoe and will be desperate to avoid a similar battle with veteran Russian veteran Mikhail Youzhny.

Federer has won all 16 head-to-head meetings with Youzhny.

Sixth seeded Austrian Dominic Thiem meets American wild card Taylor Fritz while seventh Bulgarian Grigor Dimitrov, winner of three titles this year including the US Open tuneup in Cincinnati, faces Russia's Andrey Rublev.