Spain and Serbia, led by the world's top two players, won their semifinals on Saturday and will meet in the final of the ATP Cup in Sydney on Sunday.
World No. 1 Rafael Nadal rallied to beat Australia's Alex de Minaur 4-6, 7-5, 6-1 to clinch Spain's win. Roberto Bautista Agut beat Nick Kyrgios 6-1, 6-4 to put Spain ahead 1-0.
Pablo Carreno Busta then teamed with Feliciano Lopez to beat John Peers and Chris Guccione 6-2, 6-7 (6), 10-4 to make it a clean sweep.
In the other semifinal, No. 2 Novak Djokovic held off Russia's Daniil Medvedev 6-1, 5-7, 6-4 to clinch Serbia's spot in the final.
Dusan Lajovic opened play for Serbia by beating Karen Khachanov 7-5, 7-6 (1). Nikola Cacic and Viktor Troicki wrapped up the Serbia sweep in doubles, topping Teymuraz Gabashvili and Konstantin Kravchuk 6-4, 7-6 (7).
Qatar ExxonMobil Open
Russia's Andrey Rublev, seeded second, ended the run of French qualifer Corentin Moutet with a 6-2, 7-6 (3) victory in the championship match in Doha, Qatar, on Saturday.
Rublev, 22, takes home his third tour-level title with the victory.
Moutet, 20, was playing in the first final of his career after beating top seed Stan Wawrinka in his first career semifinal.
--Field Level Media