BIRMINGHAM, United Kingdom: Andy Murray defeated Kei Nishikori 7-5, 7-6 (8/6), 3-6, 4-6, 6-3 in an epic clash as defending champions Great Britain downed Japan to reach the Davis Cup quarterfinals on Sunday.

Murray, the world No.2, had seemed set for a comfortable afternoon against his sixth-ranked opponent by taking the first two sets against a player he had defeated five times in six previous encounters.

But Nishikori battled and even was a break to the good in the deciding set before Murray stormed back for victory in five minutes short of five hours.

Victory gave Britain an unassailable 3-1 lead in the tie and a place in July’s quarterfinals.

In Belgrade, World No.1 Novak Djokovic battled for almost five hours to defeat Mikhail Kukushkin 6-7 (6/8), 7-6 (7/3), 4-6, 6-3, 6-2 to level the Davis Cup World Group first round tie between Serbia and Kazakhstan on Sunday.

Djokovic hit 19 aces and 37 winners but committed 94 unforced errors in a four hour 57-minute epic win over world No. 79 Kukushkin.

That levelled the tie at 2-2 with Serbia’s Viktor Troicki, the world No. 23, to face Aleksandr Nedovyesov in the decisive rubber later Sunday.

“This was one of the most difficult matches in my carrier both physically and mentally,” 28-year-old Djokovic told reporters.

“My opponent was near a victory, he was a better player today. After the third set I did not know what would happen, but the audience pulled me up, they have me the strength.”

In the first set the two players were almost on an equal footing but Kukushkin snatched the tie-break.

Djokovic fought back with the second set tie-break but Kukushkin dug deep, moving and playing excellently to take the third set 6-4.

However, despite fatigue and shoulder pain, Djokovic appeared more fresh than his rival in the fourth set that he won rather easily 6-3 which hinted at the final outcome.

He continued the fifth set in the same rhythm for a 6-2 win to take the rubber.

Djokovic gave his country a 1-0 lead on Friday by easily defeating Nedovyesov, the world No. 200.

But, in the second singles, Kukushkin fought back to level 1-1 by beating Troicki 7-5, 6-2, 6-4.

In Saturday’s doubles, Nedovyesov and Andrey Golubev defeated Djokovic and Nenad Zimonjic 6-3, 7-6 (7/3), 7-5.

That was Djokovic’s first loss in Davis Cup in five years.

Serbia won the Davis Cup in 2010, led by Djokovic.

The winner will go on to face defending champions Great Britain in July’s quarterfinals.