In a meeting between two of the tallest players in the Australian Open draw, 6’11” Reilly Opelka caused the biggest upset of the day to beat 6’10” John Isner 7-6(4), 7-6(6), 6-7(4), 7-6(5) on Monday.

The 21-year-old ended Isner’s nine-match unbeaten Grand Slam record against American opposition after two hours and 58 minutes, firing 40 aces to record his first Grand Slam victory. Isner also landed 47 aces in a match which featured a combined 143 winners.

Opelka’s only previous Grand Slam appearance came as a qualifier in Melbourne, falling in five sets to David Goffin in 2017. The World No. 102 improves to 2-1 against Top 10 players, having also beat then-No. 8 Jack Sock at 2018 Delray Beach.

Opelka will meet Thomas Fabbiano for a place in the third round. The Italian beat Australian wild card Jason Kubler 6-4, 7-6(1), 2-6, 6-3 in three hours and four minutes.

Grigor Dimitrov recovered from a set down to beat Janko Tipsarevic 4-6, 6-3, 6-1, 6-4. The 2017 semi-finalist (l. to Nadal), making his ninth straight appearance at Melbourne Park, fired 42 winners, including 18 aces, to advance after two hours and 33 minutes.

During the off-season, Dimitrov has continued to work with former World No. 1 Andre Agassi in Las Vegas. Agassi began work with the 2017 Nitto ATP Finals champion at the Rolex Paris Masters last November, as Dimitrov looks to make a return to the Top 10 in the ATP Rankings.

“[Andre has] done so much outside of the court,” said Dimitrov. “I’m just a better person, period. On a daily basis, I have learned something new from him.”

The 20th seed, who entered the match with a 1-4 FedEx ATP Head2Head record against Tipsarevic, improves to 3-1 this season after a run to the Brisbane International quarter-finals (l. to Nishikori). Former No. 8 Tipsarevic was making his first appearance at any level since the 2017 US Open, following surgery on both hamstring tendons.

Dimitrov will meet Pablo Cuevas in the second round. The 33-year-old Uruguayan needed just over two hours to beat Dusan Lajovic 6-4, 7-6, 6-1.

Rafael Nadal fans, exhale: Your man looked like himself.

The 2009 Australian Open champion, playing his first match of the year, looked in mid-season form on Monday against Aussie James Duckworth, beating home favourite 6-4, 6-3, 7-5 to start his Australian Open.

Nadal chased down drop shots, sprinted through forehand winners and showed a bit of his usual celebrations, ending big points with emphatic fist pumps to the crowd. His lone blemish of the day came in the third set, when at 5-3, he failed to serve out the match. But Nadal recovered with a break in the 12^th game.

The No. 2 seed hadn’t played a tour-level match since 7 September, when he had to retire from his US Open semi-final against Juan Martin del Potro because of a knee injury.

Nadal skipped the Asian swing to recover. At the Rolex Paris Masters, he had to withdraw before his first match because of an abdominal injury, and he shut down his season for good on 5 November following ankle surgery.

On Monday, however, those injuries all looked well in the past as the three-time Australian Open finalist overcame an aggressive Duckworth to avoid his another first-round exit in Melbourne (2016, l. to Verdasco). The 26-year-old Duckworth, No. 237 in the ATP Rankings, gambled against Nadal, nearly hitting more double faults (11) than aces (12) and charging the net 71 times, winning more than half of those attempts (54%).

“I’m very, very happy to be through,” Nadal said. “Not easy to come bak after a lot of months… especially against a player, he’s playing super aggressive.”

Nadal will next meet Aussie Matthew Ebden or Germany’s Jan-Lennard Struff.

Stan Wawrinka
Last year, Wawrinka made his return to action at the Australian Open following two left knee surgeries in August 2017. The 2014 champion reached the second round in Melbourne, falling to surprise quarter-finalist Tennys Sandgren, before struggling for form in the opening half of the 2018 season.

Since then, the 16-time tour-level champion has shown signs of his best level. Wawrinka pushed eventual champion Rafael Nadal at the Rogers Cup before forcing Roger Federer to three sets at the Western & Southern Open. The former World No. 3 rose from No. 263 in the ATP Rankings on 11 June to end the season at No. 66.

Wawrinka maintained that momentum in Doha at the start of his 2019 ATP Tour season, beating Rolex Paris Masters champion Karen Khachanov and World No. 43 Nicolas Jarry at the Qatar ExxonMobil Open before a straight-sets loss to eventual tournament winner Roberto Bautista Agut in the quarter-finals.

With a return to form and a 37-12 record at Melbourne Park, former champion Wawrinka should feel confident that he can once again produce his best tennis at the opening Grand Slam of the season. The 33-year-old will meet Ernests Gulbis of Latvia in the first round.

Milos Raonic
The former World No. 3 Raonic’s greatest Grand Slam performance to date may be his run the the 2016 Wimbledon final, but he has maintained great consistency at the Australian Open, too. Raonic advanced to the quarter-finals or better in three consecutive visits to the event between 2015-17. And the 6’5″ right-hander came within a set of reaching the championship match in 2016, as Andy Murray rallied from two sets to one down to beat the Canadian after four hours and three minutes. 

So if Raonic can return to the level he showed during that period, he may be able to challenge for the title once more. And quietly, Raonic is creeping back towards the Top 10 of the ATP Rankings. Last March, he fell as low as No. 40. But now World No. 17, Raonic has continued to improve his level, reaching three ATP Masters 1000 quarter-finals as well as the last eight at Wimbledon in 2018.

The Canadian No. 1 faces a stiff challenge right away in talented Aussie Nick Kyrgios, against whom he has split six FedEx ATP Head2Head meetings. But if Raonic can get past the home favourite, and potentially Wawrinka in the second round, that could be the slingshot he needs for a deep run in Melbourne.

Tomas Berdych
Berdych may have ended his 2018 ATP Tour season in June at the Fever-Tree Championships, due to a back injury. But the Czech quickly reminded fans ahead of the Australian Open that he is still capable of returning to his best level.

In the opening week of the season, Berdych reached his first final since 2017 Lyon at the Qatar ExxonMobil Open, dropping just one set en route to the championship match (l. to Bautista Agut). Berdych enters the year’s first major with great experience at Melbourne Park, having reached the quarter-finals or better in seven of the past eight years.

Berdych will meet 2018 semi-finalist Kyle Edmund in the first round, and, if he can upset the Antwerp champion, the Czech could once again make a deep run. Since reaching his first Australian Open quarter-final in 2011, Federer is the only man ranked outside the Top 10 in the ATP Rankings to beat Berdych at the event. Federer defeated Berdych in three sets en route to the title in 2017.

Jo-Wilfried Tsonga
Like Wawrinka, Tsonga is also climbing back up the ATP Rankings following left knee surgery. The Frenchman missed seven months of action on the ATP Tour in 2018 before returning at home in Metz last September.

Following his recovery, Tsonga managed to win just one of six tour-level matches to end the season at No. 239 in the ATP Rankings. But the Frenchman wasted little time in 2019 showing that he has plenty of tennis left in him. The 33-year-old impressed crowds at the Brisbane International, beating Thanasi Kokkinakis, Taro Daniel and Alex de Minaur in straight sets to reach the last four, where he fell to in-form Russian Daniil Medvedev. Tsonga’s win against De Minaur looks even more impressive now after the Aussie went on to clinch his maiden tour-level title at the Sydney International.

Tsonga returns to the Australian Open with confidence ahead of his opening match against Martin Klizan. The 2008 runner-up Tsonga owns a 36-11 record in Melbourne, having reached the quarter-finals or better in five of his 11 appearances. If Tsonga can defeat Klizan, his next match could be against World No. 1 Novak Djokovic in a repeat of the 2008 championship match.