Kei Nishikori advanced to the quarterfinals of the Shanghai Masters on the strength of a third-round, straight-sets win over American Sam Querrey on Thursday.The eighth-seed and world No. 12 Nishikori managed the match's only service break on his second match point to take the extremely well-balanced match 7-6(7), 6-4. Nishikori's quarterfinal opponent will be top seed and world No. 2 Roger Federer of Switzerland who held off Spaniard Roberto Bautista Agut 6-3, 2-6, 6-4.With 57th-ranked Querrey serving to win the first-set tiebreak, Nishikori unleashed a wicked backhand return on the Americ…READ FULL ARTICLE