Houston ATP results

Following are the results Thursday from the US Men's Clay Court Championship at River Oaks Country Club (prefix number denotes seedings):

Singles Second Round

3-Feliciano Lopez, Spain, bt Lukas Lacko, Slovakia, 7-6 (4), 6-1

4-Jack Sock, United States, bt Matthew Barton, Australia, 6-2, 7-6 (5)

Tim Smyczek, United States, bt Donald Young, United States, 6-2, 6-4

Doubles Quarterfinals

1-Bob Bryan/Mike Bryan, United States, bt Reilly Opelka/Tommy Paul, United States, 6-4, 6-3

Chung Hyeon, South Korea/Julio Peralta, Chile, bt 2-Philipp Petzschner, Germany/Alexander Peya, Austria, walkover

Victor Estrella Burgos, Dominican Republic/Santiago Gonzalez, Mexico, bt 3-Eric Butorac/Scott Lipsky, United States, 6-4, 7-6 (4)

4-Steve Johnson/Sam Querrey, United States, bt Chris Guccione, Australia, and Andre Sa, Brazil, 6-3, 2-6, 10-8

Endit