Anett Kontaveit won her first round game against former world number one Angelique Kerber of Germany in straight sets, at the Cincinnati tennis tournament on Tuesday.
Kerber was seeded 13th in the competition, properly called the Western & Southern Open, a warmer for the U.S. Open later this month.
The first set on the outdoor hard court at the Lindner Family Tennis Center in Mason, OH , was close, with Kontaveit, ranked 20th in the world, facing a tie-break situation after breaking the German's serve twice earlier in the set.
Kontaveit was lagging 5-3 in the tie break but saved the set point at 6-5 and went on to win 7-6(7).
The second set was much more of a formality, with the Estonian, 23, from Tallinn, leading 4-0 in games, before Kerber pulled two games back. Kontaveit overcame a break point in the next game, going on to win the set 6-2.
This marks the second time in recent weeks Kontaveit has defeated a grand slam winner, having beaten Maria Sharapova of Russia in a long-winded first round encounter at the Rogers Cup in Toronto.
Kontaveit faces Iga Świątek (Poland) next.
Kontaveit and her doubles partner Maria Sakkari (Greece) had already won their first round ladies' doubles game on Monday, facing Hsieh Su-Wei (Taiwan) and Barbora Strýcová (Czech Republic) in the next round. Strýcová herself, a Wimbledon semi-finalist this year, was beaten in the singles by another former Kontaveit doubles partner, Daria Kasatkina (Russia).
Editor: Andrew Whyte