GHENT, Belgium — Andy Murray gave Britain its first Davis Cup title in 79 years when he beat Belgium’s David Goffin 6-3, 7-5, 6-3 in the first of reverse singles Sunday.

The win gave Britain an unassailable 3-1 lead in the best-of-five series and the final singles match was not played.

“I can’t believe we did it,” Murray said on court. “We may never get an opportunity to do this again. We should celebrate tonight.”

Britain is the only nation to have competed in all Davis Cup editions since 1900 and its 10th title makes it the third most successful nation after the United States (32) and Australia (28).

But it was a long way coming. Britain last won it in 1936 with Fred Perry as its star and last played in the final in 1978.

Murray, ranked No. 2 in the world, is unbeaten in Davis Cup play this year.

After hitting a backhand lob that clinched the match, Murray fell on his back on the clay at the Flanders Expo arena.

His teammates piled atop him but Murray was quick to wiggle himself out and ran toward the Belgian bench to congratulate his opponents, before being hoisted by his teammates.

Murray, who ended Britain’s 77-year wait for a men’s Wimbledon champion in 2013, then sat on the British team’s bench, his face hidden behind a Union Jack flag. He now has two Grand Slam titles and an Olympic gold medal to go with the Davis Cup title.

Murray became only the third player after John McEnroe in 1982 and Mats Wilander in 1983 to achieve an 8-0 singles record in one calendar year since the introduction of the World Group in 1981.

After teaming with brother Jamie to win the doubles on Saturday, he is the first player since Pete Sampras in 1995 to win three live matches in a Davis Cup final. He is also only the second player to win 11 live matches in the same Davis Cup year after Ivan Ljubicic in 2005.

McEnroe had a 12-0 record in 1982 and Michael Stich had 11 wins in 1993.

On Friday, Goffin came back from two sets down for the first time in his career to beat Kyle Edmund in the opening singles. Murray then leveled the series by beating Ruben Bemelmans in straight sets.

Goffin, ranked No. 16, has not won a set against Murray in two previous matches on the tour.

The Belgian appeared to get a glimmer of hope when he broke Murray’s serve for the first time for a 2-0 lead in the third set. But with nine sets of tennis over two days behind him, Goffin was unable to sustain the momentum and dropped his serve in the very next game. A sizzling backhand cross-court winner gave Murray two break points and Goffin then played a forehand wide.

Murray faced a break point in the next game but hit a service winner and an ace to come out unscathed. Then, as many times during the match, he pounced on Goffin’s second serve to break the Belgian at love and regain the initiative.

Murray wasted his first match point by netting a backhand return. But the final lob was a superb shot to finish the long quest for the title as the loud British supporters exploded in joy.

British Prime Minister David Cameron, attending an EU summit in Brussels, was quick to congratulate the team.

“First of all, in another part of Belgium, let us celebrate the great Davis Cup win,” Cameron said. “Many congratulations to Andy Murray, Jamie, to the rest of the British team. First title in 79 years. Absolutely thrilling for everyone in the country, and my congratulations to them.”