WASHINGTON -- Wimbledon semifinalist Grigor Dimitrov pulled out of the Citi Open hard-court tournament, citing the flu and a sinus infection.

Dimitrov's withdrawal was announced Sunday, a day before play begins.

Dimitrov is a top-10 player who would have been seeded third at the tournament, part of the North American circuit of tuneup events ahead of the US Open.

Eugenie Bouchard, the women's runner-up at Wimbledon, withdrew from the Citi Open earlier.