Top-seeded Rafael Nadal capped off the night in Cincinnati with an easy victory in his first match since returning to the top of the tennis rankings at the Cincinnati Masters on Wednesday.
Nadal, who got a first-round bye, defeated Richard Gasquet 6-3, 6-4 to advance.
Gasquet hasn't taken a set off the 31-year-old Spaniard in 10 consecutive meetings since doing so at Toronto in 2008.
Nadal next faces compatriot Albert Ramos-Vinolas in the third round.
Nadal has a 3-0 win record against the World No 24th.
“I work every day to play better. It's obvious that was an important start for me, a good one," said French Open champion Nadal, who will claim the world number one spot on Monday.
"Now I have another opportunity tomorrow to go on court and play."
Earlier, unseeded American teenager Frances Tiafoe upset red-hot Alexander Zverev 4-6, 6-3, 6-4 to reach the third round of the Cincinnati Open.
World number seven Zverev, who stunned Roger Federer in the Montreal final last week after claiming the title in Washington DC, was on a 10-match winning streak but faded in the final set against the energetic baseliner.
It was 19-year-old Tiafoe's first win over a top-10 player and he bounded around the court in joy, thumping his chest to a standing ovation after Zverev floated a backhand long on match point with his third unforced error of the last game.
"I saw he was a bit tired, but he was still competing. It was tough. I was happy to get through it," 87th-ranked Tiafoe told Tennis Channel. "My game plan was to keep the rallies long and keep him out there and that's what I did."
Tiafoe, who notched his first top 50 win in Wimbledon, will meet big-serving American John Isner next up.
Bulgarian seventh seed Grigor Dimitrov beat Feliciano Lopez 7-6(5), 6-4 to set up a last-16 clash with Juan Martin Del Potro.
Dimitrov nearly broke the unseeded Spaniard three times prior to making a strong start in the tiebreak and went on to register 27 winners in the match.
The 28-year-old Del Potro advanced with a 6-4, 6-4 win over American qualifier Mitchell Krueger, winning each set on a late break.
Del Potro, who on Tuesday ousted 10th-seeded Czech Tomas Berdych, saved five break points at 3-3 in the second set and clinched victory on his fourth match point.
Dimitrov has not beaten Del Potro in five career meetings, with the most recent defeat coming at Rome in May.
Australian Nick Kyrgios beat Ukraine's Alexandr Dolgopolov 6-3, 7-6(6) to reach the third round, where he will face unseeded Croatian Ivo Karlovic.
Also advancing to the round of 16 were Spaniards David Ferrer and Pablo Carreno Busta, and Russian Karen Khachanov.
Among Indians at the tournament, tennis ace Sania Mirza and her Chinese partner Peng Shuai showcased a splendid performance as they booked their place in the quarter-finals of 2017 Western and Southern Open in Cincinnati following a straight-set victory in the women's doubles clash here on Thursday.
The fourth-seeded pair looked dominant throughout the match as they went on to post a comfortable 7-5, 6-4 win over the German- Ukraine duo of Julia Gorgesand and Olga Savchuk in a last-16 clash that lasted one and a half hour.
The Indo-German duo of Mirza and Shuai will now cross swords with the Romanian team of Irina-Camelia Begu and Raluca Olaru for a place in the last four.
Sania's compatriot Ramkumar Ramanathan could not extend his run at the Cincinnati Masters, falling yet again to American Jared Donaldson.
In a second round singles match, the lucky loser suffered a 4-6, 6-2, 4-6 loss to the local wild card.
It was second consecutive defeat for Ramkumar against the American, having lost to him in the second round of the Roland Garros Qualifier in 2015.
After Ramkumar's defeat, India's interest in the tournament remains in doubles with Rohan Bopanna set to play his second round match with partner Ivan Dodig.
They face Colombia's Juan Sebastian Cabal and Italian Fabio Fognini, who both are top-25 singles players.
Pliskova on track to defend Cincinnati title, Venus out
Karolina Pliskova celebrated her return to the tournament that helped launch her rise to world number one with a 6-2, 6-3 win over Russian Natalia Vikhlyantseva in the second round of the Cincinnati Open on Wednesday.
Two celebrated seeds fell, with number three Angelique Kerber and ninth-seeded Venus Williams upset in three-setters, disrupting their U.S. Open preparations.
Kerber lost 6-4, 1-6, 7-6(11) to Russian Ekaterina Makarova, while Williams was upset 6-3, 2-6, 6-2 by Australian qualifier Ashleigh Barty in second-round matches.
Barty will face former world number one Caroline Wozniacki, a 6-2 6-4 winner against Russia's Elena Vesnina, in the last 16.
Top seed Pliskova rose to the occasion on the key points.
She saved all five break points she faced, while losing just three points behind her first serve against the Russian, who reached her first WTA final at Den Bosch in June.
Last year Pliskova beat Kerber in the Cincinnati final, stopping the German from ascending to number one with the biggest victory of her career up to then.
Pliskova went on to have a brilliant Flushing Meadows run, beating both Venus and Serena Williams on the way to the final, sparking a consistent stretch that helped her succeed Kerber atop the rankings after Wimbledon.
Next up for the 25-year-old Czech is a third-round match against Italian Camila Giorgi, who beat Australian Daria Gavrilova 7-6(1), 5-7, 6-3.
American 16th seed Madison Keys beat Russian Daria Kasatkina 6-2, 6-1 to reach the last 16, where she will face Wimbledon champion Garbine Muguruza of Spain.
For the second week in a row, American Sloane Stephens defeated 14th seed Petra Kvitova, who was bothered by pain in her right thigh, to reach the third round with a 6-2 6-3 win.
Stephens, sidelined almost a year due to a foot injury before returning at Wimbledon, beat Kvitova last week in three sets in Toronto on her way to the semi-finals.
Up next for Stephens will be the on-form Makarova.
Japan's Nishikori to miss rest of season with wrist injury
Japan's Kei Nishikori will miss the rest of the 2017 season after tearing a tendon in his right wrist, his manager said on Wednesday.
The 27-year-old world number nine becomes the latest of a clutch of high-ranked players to take time out from the sport due to injury.
Fourth-ranked Stan Wawrinka and number five Novak Djokovic have in recent weeks called a halt to their seasons to recover from knee and elbow injuries respectively.
Nishikori was scheduled to play at this week's Cincinnati Masters, a warm-up event for the US Open, but withdrew when he felt a sharp pain in his wrist during practice on Sunday.
"Kei hit a serve and heard a 'pop' in his wrist," his manager said in a statement.
"It has become clear that Kei has a tear in one of the tendons in the right wrist.
"At this stage, we have elected not to do surgery and Kei is in a cast. After the swelling comes down in the next weeks, we will evaluate next steps. Kei will withdraw from all the 2017 tournaments and work hard to be ready for next year."
The Japanese reached his only grand slam final at the US Open in 2014, losing to Croatia's Marin Cilic.
Injury worries have also forced four other top-ten players -- Cilic (adductor), Roger Federer (back), Andy Murray (hip) and Milos Raonic (wrist) -- to miss Cincinnati.
