Rising star Jared Donaldson will meet second seed Stan Wawrinka in the second round of the Western & Southern Open after beating Nicolas Almagro.
Rhode Island-born Donaldson, 19, downed former top-10 Spaniard Almagro 6-3 7-6 (7/2) in 91 minutes, winning 84 per cent of his first serve points.
Another teenager, 18-year-old Reilly Opelka of Florida, will encounter Jo-Wilfried Tsonga following his 3-6 7-5 7-6 (11/9) triumph over Jeremy Chardy.
Third seed Rafael Nadal will open his Cincinnati campaign against Pablo Cuevas, who downed Sam Querrey 4-6 7-6 (7/5) 6-3 in the first round.
France's Julien Benneteau upset number 10 seed David Ferrer 6-4 2-6 6-4 while Marin Cilic defeated Viktor Troicki 6-3 6-4 inside 62 minutes.
Elsewhere, Grigor Dimitrov edged out Gilles Simon 6-1 6-3 and Kevin Anderson progressed when Alexandr Dolgopolov retired hurt at 7-5 0-0.
Source: PA
