India's Sanam Singh lost to Peter Polanski for the second time in two months and crashed out of the ATP Knoxville Challenger event in the United States.
Ramkumar, Poonacha and Saketh Myneni had a light session that lasted two and a half hours.
Nagal is likely to reach a new career-high ranking of world No. 92
The duo, who had won the Australian Open earlier this year, overcame several unforced errors in the first set to win the gruelling quarterfinal 3-6, 7-6 (4), 10-7.
Images from the men's singles Round of 16 matches at the US Open on Monday.
Meanwhile, Sumit Nagal was trailing in his second round men's singles match against Holger Rune of Denmark, when rain led to a suspension of the contest.
Djokovic's sixth trophy this season helped him to extend his lead over the second-ranked Carlos Alcaraz in the race to the year-end number one spot
Sumit Nagal had to be content with a runner-up finish at the ATP Tulln Challenger event after losing the singles title clash in straight sets to Czech Republic's Vit Kopriva, in Tulln on Sunday.
Chile's Marcelo Rios suffered yet another home defeat in the final of the Bellsouth Open.\n\n
Iga Swiatek and Coco Gauff stressed the need to start matches earlier at Grand Slams
Zverev has consistently denied all the allegations.
Cypriot Marcos Baghdatis and Frenchman Jo Wilfried Tsonga joined the list of high-profile pull-outs from the ATP tournament, to be played at the CCI, Mumbai, from September 24 to 30.
Dimitrov has enjoyed the best season of his career in 2017, clinching four titles overall, including his first Masters title in Cincinnati.
Tabilo broke the top seed four times on Centre Court while not conceding a single break point.
Britain's Andy Murray joined world number one Novak Djokovic and newly-crowned US Open champion Rafa Nadal as definite qualifiers for the ATP World Tour finals on Tuesday, but Roger Federer faces an uphill task to make the eight-man field.
Fresh from winning the Chennai leg, Yuki Bhambri advanced to the second round, even as the other two Indians Saketh Myneni and Vishnu Vardhan made quiet exits in the $50,000 ATP Challenger at BTA Courts in Kolkata.
Factbox on Carlos Alcaraz, who beat seven-time champion Novak Djokovic
'I think it only happens in France. At Wimbledon, obviously, there's not that. Or in Australia either. At the US Open, it's still rather quiet. Here, it's a really unhealthy atmosphere.'
It was the 31-year-old Serb's second comfortable win in the Gustavo Kuerten group and combined with Marin Cilic's 6-7(2), 6-3, 6-4 defeat of American John Isner later in the day, he sealed his place in the semi-finals at the year-ender for the eighth time.
Carrying forward their good work at the Davis Cup, India's Somdev Devvarman and Rohan Bopanna have qualified for the BNP Paribas Open, an ATP Masters tournament in Indian Wells on Thursday.
World No 4 Del Potro is still sidelined with a right knee injury sustained in Shanghai last month.
The Indo-Pakistan tennis duo of Rohan Bopanna and Aisam-ul-Haq Qureshi has booked a berth in the season-ending ATP World Tour Finals to be held from November 20 to 27 at London's O2 arena.
Alexander Zverev became the first German to reach the last four at the ATP Finals for 15 years as he beat American John Isner 7-6(5), 6-3 at the O2 Arena on Friday.
Croatia's Ivo Karlovic posted a 6-4, 6-1 victory over Argentine Mariano Zabaleta in the Houston final.
Images from the men's singles action at the US Open on Sunday.
The US Open's decision to extend the 2013 tournament to a third Monday has drawn criticism from the men's govening body the ATP who have called on Flushing Meadows organisers to fall into line with the three other grand slam tournaments.
Somdev Devvarman could not qualify for the Wimbledon singles but that did affect his rankings as the Indian rose a rung to career-best 103 in the latest ATP list issued on Monday.
The US $380,000 ATP Tour event will be held at the newly-laid synthetic courts of the CCI in Mumbai, in September.
Novak Djokovic said he is still hoping for a final chapter in their storied rivalry.
Rohan Bopanna's and Aisam-ul-Haq Qureshi's wait for their first ATP title continued after they lost the final of the Pilot Pen Tennis tournament to Wimbledon finalists Robert Lindstedt and Horia Tecau in New Haven, USA.
World number one Novak Djokovic will bid for a record fourth successive ATP World Tour Finals crown in London later this year after becoming the first man to qualify for the season-ender.
The Monte Carlo Masters begins on Sunday. Nadal has won the event a record 11 times, with his last victory coming in 2018.
A few days after it appeared as though a Roger Federer impersonator had gatecrashed the 02 Arena, the Swiss great resumed normal service to outplay Kevin Anderson and reach the last four of the ATP Finals on Thursday.
Carlos sought tranquility in Cabo San Lucas, Mexico, accompanied by his brother Alvaro and friends.
Somdev Devvarman and Praksh Amritraj moved to the pre-quarterfinals of the $1,25,000 ATP Challenger event in Seoul, Korea after winning their respective first round matches.
Bopanna also spoke about the challenging conditions at the Australian Open and having to push his boundaries to get them wins.
The win at the Chennai Open challenger event on Sunday pushed Nagal to 98th in the latest singles rankings.
Harsh Mankad reached the men's doubles finals of the USD 50,000 ATP Challenger tournament in the United States but it was curtains for Somdev Devvarman, who lost the semi-finals along with Treat Conrad Huey.
