Three-time champion Kei Nishikori got his bid for a fourth straight Memphis Open title under way on Wednesday with a 6-2, 7-5 triumph over American Ryan Harrison. The top seed extended his winning streak to 14 matches in Memphis with the one-hour, 21-minute result.

Nishikori had won the pair’s two prior FedEx ATP Head2Head meetings coming into the night clash, including a three-set affair at the same stage of last year’s tournament. After Harrison held his opening service game, the World No. 7 in the Emirates ATP Rankings put the pedal down, reeling off five games in a row, converting on two of three break points before the American could hold again. 

Nishikori secured the opening set on his first opportunity after 27 minutes before his 124^th-ranked opponent mounted a challenge late in the second. With Nishikori serving for the match at 5-4, Harrison converted his first break of the match on his fifth chance. He saved four match points in the process.

His joy was short-lived, however. Nishikori broke again for 6-5 and closed it out with a love hold on his fifth match point to move through to a quarter-final clash with Kazakhstan’s Mikhail Kukushkin, an earlier 6-1, 7-5 winner over No. 5 seed Denis Kudla.

Jo-Wilfried Tsonga has made a successful South American debut at the Argentina Open on Wednesday, easing past local Leonardo Mayer 6-1, 6-2 to advance to the quarter-finals. The French World No. 9 in the Emirates ATP Rankings powered through the opening set against the 37^th-ranked Argentinian, breaking twice to take it in just 25 minutes.

The 30 year old was similarly dominant in the second set, breaking Mayer for 2-1 before racing to 3-1 with a love hold. He secured the double break for 5-2 and closed it out on his second match point in just shy of an hour. The defeat consigned Mayer to his eighth straight loss against Top 10 opponents, with his lone victory in 25 matches coming against World No. 7 David Ferrer in the 2014 Hamburg final.

Coming off a semi-final run in Auckland and fourth-round showing at the Australian Open, Tsonga is looking to reach his first claycourt final in Buenos Aires this week.  He moved to within two victories of doing so and will next meet Spaniard Nicolas Almagro, a player he holds a 6-0 FedEx ATP Head2Head record against. Almagro earlier produced a 6-3, 4-6, 6-4 result to beat Argentine Federico Delbonis.

Mikhail Kukushkin is yet to drop a set in Memphis after defeating fifth-seeded American Denis Kudla 6-1, 7-5. The Kazakh went five-for-10 on break point opportunities in the 81-minute match.

“I started well, but from the middle of the second set, he started playing much better,” Kukushkin said. “There were lots of tough points for me. I needed to fight for every game. Maybe I was a little bit lucky to win, but I am happy to be through to the quarter-finals.

“I was hitting well and not making too many unforced errors. It helped me that [Kudla] started slowly. From the middle of the second set he started to play much better … a lot of long rallies, tough points for me.

“I had to fight a lot to win every game. Maybe the score looks very easy, especially the first set, but then second set was really tough.”

 The win sets up a potential showdown with three-time defending champion and top seed Kei Nishikori who was due to face Ryan Harrison in the night session. The Japanese world No. 7 holds a perfect 5-0 FedEx ATP Head2Head record against Kukushkin.

“If I have to play him, for sure it’ll be a tough match,” Kukushkin said. “He’s a Top 10 player. I’ve played him a few times and lost all of them … I will just try to control everything I have and just enjoy the game.”

Nishikori’s countryman, qualifier Yoshihito Nishioka, earlier cruised into the quarter-finals after dismissing Ukraine’s Illya Marchenko 6-1, 6-3. The Japanese left-hander has played himself into peak form having won through qualifying.

“I’ve been playing a lot of qualifying matches, and my confidence is good right now,” Nishioka said. “Every time I play, I think I can get to the main draw.”

The Mie native is into his second ATP World Tour quarter-final (2015 Delray Beach) and is not at all intimidated by the prospect of facing the tournament’s top seed in the semi-finals.

“I’m very excited to be in my second ATP quarter-final,” Nishioka said. “And if I win one more match, maybe I will get to play against Kei [Nishikori].”

First, Nishioka will have to find a way past No. 4 seed Sam Querrey, who had a routine 6-3, 6-4 triumph over Swiss qualifier Henri Laaksonen. The American World No. 58 hit seven aces and won 83 per cent of first-serve points in the 52-minute encounter. 

Human highlight reel Dustin Brown is at it again.

The spectacular German showed off another part of his arsenal at the Bergamo Challenger in Italy on Wednesday. Seemingly in trouble after hitting a half-volley, Brown went behind-the-back for a clean winner off his opponent’s passing shot.

Confidence matters on the tennis court, and World No. 72 Nicolas Almagro is well on his way to recapturing it at the Argentina Open in Buenos Aires.

The Spaniard, once ranked No.9 in the Emirates ATP Rankings, continued his quest for a first ATP World Tour title in four years by advancing to the quarter-finals with a hard-fought 6-3, 4-6, 6-4 win over home hope Federico Delbonis.

Almagro is coming off two injury-marred seasons after averaging over 45 wins per year between 2010 and 2013, but he is back in familiar territory in South America. The 2011 champion, who netted 16 of his 18 match wins on clay last season, improved to 27-9 in Buenos Aires. It took two hours and 13 minutes for Almagro to earn his third match win of the season, during which he held 14 break points (3/14).

In the quarter-finals, he will face either third seed Jo-Wilfried Tsonga or Argentine Leonardo Mayer.

Rising star Dominic Thiem was a point away from being upset by qualifier Gastao Elias before flipping the script and prevailing 3-6, 7-6(7), 6-3.

The Austrian made a slow start, dropping both break points faced in the opening set against an opponent who was playing in his first tour-level event of the year. The fifth-seeded Thiem got up to speed in the second set, but Elias held strong, turning aside five break points and holding a match point at 7/6 in the tie-break. It was then that the youngest player in the Top 20 showed his quality, reeling off the next three points to even the match and eventually winning in two hours and nine minutes.

Thiem, who captured all three of his ATP World Tour titles on clay, will face Dusan Lajovic, after the Serb saved a match point in the tiebreak to upset American No. 4 seed John Isner. Lajovic had lost the only prior FedEx ATP Head2Head encounter between the two but emerged a narrow 7-6(10), 4-6, 7-6(6) victor on Wednesday. The 25-year-old World No. 79 did not have a break point throughout the two-hour, 20-minute clash but managed to save five of the six break points he faced.