The American duo won 5-7, 6-1, 13-11 as they added the season-ending crown to the Wimbledon and US Open titles.
India's singles challenge has already ended with both Sumit Nagal and Ramkumar Ramanathan making first round exits.
Danish teenager Holger Rune fought back from a set down to beat hot favourite Novak Djokovic 3-6, 6-3, 7-5 and win his first Masters title in Paris on Sunday.
Croatian Ivan Ljubicic captured his first ATP title in two years when he dismissed France's Michael Llodra 7-5, 6-3 in the final of the Lyon Grand Prix on Sunday.
Jannik Sinner retained his Australian Open title with an emphatic 6-3, 7-6(4), 6-3 win over Alexander Zverev on Sunday
Defending champions Italy moved into the Davis Cup final after a 2-0 win over Australia on Saturday as Jannik Sinner defeated Alex de Minaur in straight sets to follow up Matteo Berrettini's victory over Thanasi Kokkinakis.
Rafael Nadal's hopes of winning the year-ending ATP Finals for the first time live on after the Spaniard beat defending champion Stefanos Tsitsipas 6-4, 4-6, 6-2 on Thursday.
German teenager Alexander Zverev won his first ATP Tour singles title with a 6-2, 3-6, 7-5 upset win over Switzerland's world number three Stan Wawrinka at the St Petersburg Open on Sunday.
Australia now have the opportunity to avenge last year's final defeat by Italy after world number one Jannik Sinner inspired the holders to a 2-1 victory over Argentina.
Carlos Alcaraz won two matches to lift Team Europe to a 13-11 victory over Team World for the Laver Cup title in Berlin.
The ATP Finals, in its 50th edition, is being staged in London's O2 Arena for the 12th and last time before it moves to Turin and sadly plans for a vibrant farewell party in front of the usual sell-out crowds has been scuppered by the COVID-19 pandemic.
Britain's Cameron Norrie fought back from a set down to beat world number two Carlos Alcaraz 5-7, 6-4, 7-5 in the Rio Open final on Sunday.
Novak Djokovic's bid for a 100th ATP Tour title gained momentum on Thursday
Swiatek downs Gauff to meet Sabalenka in Italian Open final
-French flair topped American firepower as Gael Monfils turned back the clock to dump fourth seed Taylor Fritz out of the Australian Open on Saturday and celebrate his place in the last 16 with a dance on court.
Debutant Stefanos Tsitsipas crushed defending champion Alexander Zverev 6-3, 6-2 on Wednesday to book his place in the last four of the ATP Finals with a match to spare.
Retired tennis great Andy Murray has agreed to join Novak Djokovic's team and will coach him at the Australian Open next year, the Serbian 24-times Grand Slam champion said on Saturday.
'It's one of the most epic matches I have played on this court, on any court really.'
Sinner remains the man to beat at Melbourne Park even as doping officials seek a two-year ban for the world number one for failing two drugs tests last March.
World number two Nadal's fate will rest on his final group match against Tsitsipas.
Aisam Qureshi beat Korea's An Jae Sung in the final to capture his first ATP Challenger title.
Learner Tien is the youngest American man to reach the third round of the Australian Open since an 18-year-old Pete Sampras in 1990.
American qualifier Steve Johnson is through to his first ATP Tour semi-final after an emphatic victory at the Delray Beach Open on Friday.
Former world number one Novak Djokovic, the last surviving member of tennis' "Big Four", said he does not plan on stopping any time soon but admitted that the retirement of rivals Roger Federer, Andy Murray and Rafa Nadal has been overwhelming.
Rohan Bopanna and Eric Butorac claimed the doubles title in Los Angeles with a 7-6, 7-6 win over Travis Parrott and Dusan Vemic.
Up next for Murray is either eighth seed Pablo Cuevas or Bolivia's Hugo Dellien, who meet in the first round on Wednesday.
The hosts had blanked Germany in their opening tie and became the first to seal a quarter-final spot with their second 3-0 win in the inaugural team event.
Sasikumar Mukund will aim for a winning return to the Davis Cup fold as India faces Togo in the World Group I Play-off.
Djokovic saved three breakpoints in stifling conditions to go 5-4 up but lost the opening set in a tough tiebreak as Opelka cranked up his serve
Jannik Sinner spearheaded Italy's charge towards a second successive Davis Cup title with a 2-0 victory over the Netherlands in the final at the southern Spanish city of Malaga on Sunday.
The 32-year-old debutant at the ATP's blue riband event won the first 11 games of the round-robin clash before a relieved Nishikori finally got on the scoreboard with an angled winner.
Novak Djokovic ruthlessly took Matteo Berrettini apart at the ATP Finals on Sunday as he began his quest to reclaim the number one ranking by winning his opening group match 6-2, 6-1.
The top-seeded Indian pair of Yuki Bhambri and Saketh Myneni rallied from a set down to beat Christopher Rungkat and Akira Santillan and win the Bangkok Open title, their sixth together on the ATP Challenger Tour, in Nonthaburi, Thailand, Saturday.
The 14-times Grand Slam champion will surpass Roger Federer as world number two when the next edition of the ATP rankings are released on Monday.
Prajnesh Gunneswaran announces retirement from professional tennis
Sinner gives the impression of a player with all the answers against whoever he comes up against, but the off-court questions he is likely to face about the doping case that surfaced in August might be harder to shrug off.
Medvedev became only the fourth player in ATP history to beat the world's top three at the same tournament.
Rohan Bopanna and his Australian partner Matthew Ebden sailed into the men's doubles final at the Miami Open.
Indian Davis Cupper Yuki Bhambri clinched his first doubles title of the season with partner Adrian Menendez-Maceiras, following a nerve-wracking win in the rain-hit final of the ATP Challenger event in Karshi, Uzbekistan on Saturday.
Novak Djokovic was seriously rattled early on by inspired American teenager Nishesh Basavareddy but rallied for a 4-6, 6-3, 6-4, 6-2 victory on Monday.
