Kei Nishikori, Jack Sock reach Miami Open quarterfinals

KEY BISCAYNE, Fla. (AP) Kei Nishikori rallied in the final set to beat Argentina's Federico Delbonis on Tuesday and reach the Miami Open quarterfinals.

Nishikori, the No. 2 seed and Key Biscayne finalist last year, won 6-3, 4-6, 6-3. The Japanese star was down a break early in the third, then took five of the final six games.

Unseeded Fabio Fognini of Italy awaits Nishikori in the quarterfinals. Fognini topped Donald Young 6-0, 6-4.

Young's loss meant only one American man would reach the round of eight. That would be No. 13 Jack Sock, who beat Jared Donaldson 6-2, 6-1.

Roger Federer, Stan Wawrinka, Caroline Wozniacki and Rafael Nadal are among those to play later Tuesday.