In the Dallas Open quarterfinals, Marcos Giron stunned first seed Frances Tiafoe
In the Dallas Open, the top seed was hoping for a fight.For the second time in three years, the unseeded Marcos Giron defeated Tiafoe early on and cruised to a 6-1, 6-4 victory on Friday night to advance to the SMU campus’s hardcourt tournament quarterfinals. At No. 14, Tiafoe is the highest-ranked player and is…