Top seed Simona Halep beat Sloane Stephens of the US 7-6 (3), 6-0 in her opening match at the Washington Open on Tuesday.
Stephens, a winner here in 2015, has just returned from a year out with a foot injury and was brushed aside by the Romanian after she took a set to get up to speed.
Halep, a quarter-finalist at Wimbledon, will now face Mariana Duque-Marino in the second round.
— WTA (@WTA) August 2, 2017
Also on Tuesday, Russia’s Ekaterina Makarova beat American Jamie Loeb 7-6 (4), 6-3, while Monica Puig of Puerto Rico beat Louisa Chirico 6-4, 6-4.
In the only other women’s match to be played on Tuesday, Britain’s Heather Watson lost out to Romanian Patricia Maria Tig in two tiebreaks.
Watson, who had won two qualifiers just to take part, wasted a set point in the opener, but eventually lost out to Tig after just over two hours.
Delays for storms meant that all the women's night matches were postponed until Wednesday.