BELGRADE, Serbia (AP) Kyle Edmund stepped into the role of Andy Murray and took titleholder Britain into the semifinals of the Davis Cup by beating Dusan Lajovic of Serbia in straight sets in the first of the reverse singles on Sunday.

Edmund's 6-3, 6-4, 7-6 (5) win on a wet and windy day at the outdoor Tasmajdan clay-court stadium gave Britain an unassailable 3-1 lead in the best-of-five series.

The 21-year-old Edmund also won his opening singles on Friday against Janko Tipsarevic as he assumed the role of Murray as the leader of the team.

''It's always a team effort, but in the back of your mind you know what's on (the) line,'' Edmund said. ''It's great to win for the country.''

Murray decided not to play in the quarterfinals a few days after his second Wimbledon title but cheered the team on from the sidelines.

In the final and meaningless match, Janko Tipsarevic beat James Ward 6-2, 3-6, 7-5 to leave the final score at 3-2 for Britain. Britain hosts Argentina in September in the semifinals.

''It's a big difference if Andy plays or not, but Kyle didn't show any inexperience. He knows how to play on clay. He has a great forehand with a lot of spin,'' Lajovic said.

Serbia played without Novak Djokovic, the top-ranked player in the world, and the country's No. 2 Viktor Troicki. Djokovic took a brief break from tennis after his shock third-round exit from Wimbledon and did not come to his native Belgrade. Troicki said he wanted to prepare for the upcoming tournaments.

Edmund had to save two set points in the third set before holding serve and he won despite falling behind 4-2 in the tiebreaker.

Lajovic sent a wild backhand way wide to give Edmund a match point and the Briton converted when Lajovic hit another backhand wide.

''There were no easy points. It's nice that I was able to get back into it,'' Edmund said.

Edmund had broken serve for a 4-3 lead in the final set but dropped his serve for the first time in the match in the 10th game.

Britain's captain Leon Smith was full of praise for Edmund.

''He has every reason to be immensely proud. He was brilliant today,'' Smith said.

''He's improved so much physically. His forehand is so huge, such a great shot. His serve is better, his backhand is rock solid.''

Edmund had breezed through the first set, finishing it off with two straight aces in the drizzle.

But the light rain stopped at the start of the second, with Edmund breaking for 4-3 and closing it with a service winner.

Edmund's huge forehand gave him 27 of 39 winners, while Lajovic finished with 21 winners.

''The forehand is his best weapon and it made the difference today,'' Lajovic said. ''I feel I did the best I could under the circumstances. He was the better player today.''

Edmund was the highest ranked player in the two teams at No. 67.