KEY BISCAYNE, Fla. — Three-time Grand Slam runner-up Andy Murray lost Friday in his opening match at the Sony Ericsson Open to American qualifier Alex Bogomolov Jr., 6-1, 7-5.

KEY BISCAYNE, Fla. — Three-time Grand Slam runner-up Andy Murray lost Friday in his opening match at the Sony Ericsson Open to American qualifier Alex Bogomolov Jr., 6-1, 7-5.

Following Murray's departure, Novak Djokovic improved to 19-0 in 2011 by drubbing Denis Istomin 6-0, 6-1. Djokovic's record is the best to begin a year since Ivan Lendl started 25-0 in 1986.

Murray, meanwhile, has lost nine consecutive sets, a remarkable drought for a player ranked fifth in the world.

Donald Young was ranked 143rd when he upset Murray two weeks ago at Indian Wells. Bogomolov is ranked 118th, and his only other win over a top 10 player came in 2002, his senior year in high school, when he beat No. 3 Tommy Haas in Los Angeles.

While his victory gave U.S. tennis fans something to brag about, the last American in the women's draw was eliminated in the second round when Varvara Lepchenko lost to Petra Kvitova 6-1, 6-2.

American women went 4-7 in the tournament, with none winning more than one match and none reaching the final 32.

Defending champion Kim Clijsters needed only 50 minutes to win her opening match, beating qualifier Anastasiya Yakimova 6-1, 6-1.

In other men's play, Americans Mardy Fish, Sam Querrey, John Isner and James Blake reached the third round. Juan Martin del Potro also won.