Andrei Kuznetsov's win against Mikhail Kukushkin of Kazakhstan in Moscow on Sunday secured Russia's return to the Davis Cup World Group after a four-year absence. 

Kuznetsov's 6-1, 6-2, 6-2 win lifted Russia into an unassailable 3-1 lead and into the elite group for the first time since 2012.

Kuznetsov, ranked 47th in the world, broke Kukushkin's serve twice in both the first and second sets for a commanding two-set lead after just over an hour on court.

In the third set, the 25-year-old Russian broke his opponent twice.

"I managed to keep concentration throughout the match," Kuznetsov said in interview on Russian television.  

"And we will all be happy to play for our country in the World Group next year."

Earlier, Konstantin Kravchuk and Andrey Rublev beat Kazakhstan's Aleksandr Nedovyesov and Andrey Golubev 6-3, 6-7 (3/7), 6-2, 7-5 in under three hours in the doubles.

In the fourth set the visitors broke early, but the Russian pair broke back twice to take the set and match in just under three hours.

"We were all nervous because it was a very important match for both teams," Kravchuk said.
"We made plenty of mistakes today but luckily managed to win."

Earlier Kukushkin levelled the score, beating Russia's Evgeny Donskoy in a tough five-setter.
The 28-year-old won 6-7 (7/9), 6-2, 4-6, 6-2, 6-2 in a game held over due to bad light with the score at two sets all on Saturday.

"I had no choice but to be at my best from the start because only one set was left," Kukushkin said.   "Luckily, everything went my way."

On Saturday Kuznetsov put Russia in the lead with a confident win over Nedovyesov 6-3, 6-4, 5-7, 7-5 after rain had delayed the start of the tie.