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The 2017 season featured a number of stunning ATP upsets, including Vasek Pospisil's win against World No. 1 Andy Murray in Indian Wells.

The Five Biggest ATP World Tour Upsets of 2017

ATP World Tour Season In Review: Biggest ATP Upsets

Continuing our Season In Review series, ATPWorldTour.com revisits the top 5 ATP World Tour upsets of 2017.

(5) Vasek Pospisil d. Andy Murray 6-4, 7-6(5) – BNP Paribas Open Second Round

Vasek Pospisil has the game to beat the top players. In January 2014, he reached No. 25 in the Emirates ATP Rankings, and a year later, he was in the quarter-finals of The Championships, Wimbledon (l. to Murray). His serve-and-volley game can flummox the greatest.

So even though Pospisil had been beset with injuries and had a triple-digit number (No. 129) next to his name, the Canadian, who had recently started working with former doubles No. 1 Mark Woodforde, surely believed he could shock the BNP Paribas Open and knock off World No. 1 Andy Murray.

The Scot had never won the BNP Paribas Open title in Indian Wells, and he had suffered early setbacks in the past, falling in the second round three times (2006, 2011, 2012).

But, after a disappointing Australian Open, Murray looked determined to pen a new Indian Wells story for himself. He led 4-2 in the opener and was having little trouble with Pospisil's big game, having broken the 6'4” right-hander in the fourth and sixth games.

But the Canadian came alive, winning six straight games to gain a set and a break lead. Pospisil was darting around the court, and the crowd was loving his aggressive, old-school style.

Murray rallied to force a second-set tie-break, but Pospisil stayed on offence and didn't back away from the challenge, earning the biggest win of his career with a forehand winner. He tossed his racquet into the sky to celebrate.

“If I pick a handful of great moments in my career, this is definitely one of them,” Pospisil said. “To beat the No. 1 player and somebody as accomplished as Andy, one of the greats of the game, is amazing.”

(4) Damir Dzumhur d. Stan Wawrinka 7-6(4), 6-3 – Dubai Duty Free Tennis Championships First Round

Defending champion Stan Wawrinka entered the Dubai Duty Free Tennis Championships on a roll. The Swiss right-hander had fallen just short of reaching his fourth Grand Slam final at the Australian Open (l. to eventual champion Federer in five sets).

Wawrinka's first-round match against Damir Dzumhur of Bosnia-Herzegovina in Dubai looked as if it'd be a “get-used-to-the-conditions” match. Wawrinka had a 3-0 lead after about eight minutes, and Dzumhur could hardly keep the ball in play. “Stan The Man” was blasting forehands from the centre of the court and teeing off on Dzumhur's second serve.

But the 5'9” Bosnian chased down more balls and hoped Wawrinka would slow down, which eventually happened, and Dzumhur earned the biggest win of his career with some exhausting defence and clutch serving. “I was fighting. I was grinding,” Dzumhur said.

The career-best win at the time foreshadowed a career year for Dzumhur. He went on to win his first and second ATP World Tour titles (St. Petersburg, Moscow), becoming the first Bosnian to claim an ATP World Tour crown. At the start of the season, Dzumhur was No. 82 in the Emirates ATP Rankings. He will finish 2017 at a career-high No. 30.

(3) David Goffin d. Roger Federer 2-6, 6-3, 6-4 – Nitto ATP Finals Semi-final

You have to appreciate the honesty. The day before David Goffin celebrated the “best win” of his career, beating Roger Federer to reach the championship of the Nitto ATP Finals, the Belgian was asked what he planned to do differently against Federer.

The 26-year-old Goffin had never beaten the Swiss right-hander, coming up short in all six of their FedEx ATP Head2Head matchups, including a 6-1, 6-2 drubbing weeks earlier at the Swiss Indoors Basel.

What would Goffin do differently? He wasn't sure. “Honestly, I don't know what to do,” he said.

Goffin had been up and down at the Nitto ATP Finals. He upset World No. 1 Rafael Nadal but then, two days later, won only two games against Grigor Dimitrov. Goffin reached the semi-finals by beating fourth seed Dominic Thiem in a 'win and you're in' round-robin match.

So which Goffin would show against Federer? Or maybe it didn't matter which Goffin arrived, as all tournament, Federer had been clear about his intentions – a record-extending seventh Nitto ATP Finals title. The 36-year-old had finished Group Boris Becker play a perfect 3-0, and Federer was 16-0 against the other three semi-finalists – Goffin, Jack Sock of the U.S. and Bulgarian Grigor Dimitrov.

Exactly what Goffin did not want to happen – a repeat of their Basel matchup – looked like it was occurring in the first set. Federer was dominating, cutting shoestring volleys for winners and blistering backhands. But Goffin gradually relaxed and grew in confidence, and he forced a third set, where he had thrived all year.

He entered the semi-finals 21-5 in deciding sets, and even in one of the biggest arenas in tennis, Goffin held his nerve. He broke in the third game and served out the match on his first opportunity.

“As soon as I had the chance to go for the shot from the return and from the serve, [that] was the key, to go for the shot,” Goffin said.

He became the first player to beat the Top 2 players at the Nitto ATP Finals since 2009, when champion Nikolay Davydenko beat No. 2 Nadal in group play and No. 1 Federer in the semi-finals. The Belgian also became the sixth player ever to beat Nadal and Federer in the same tournament and the first since Novak Djokovic at the 2015 Nitto ATP Finals.

(2) Denis Shapovalov d. Rafael Nadal 3-6, 6-4, 7-6(4) – Coupe Rogers in Montreal Third Round

A long-awaited return to No. 1 was in Rafael Nadal's sights, but an excited Canadian with wavy blonde hair had other ideas. Eighteen-year-old Denis Shapovalov had saved four match points in his Coupe Rogers opener to beat Brazil's Rogerio Dutra Silva, and he had then dismissed Argentina's Juan Martin del Potro in straight sets for the biggest win of his life.

Nadal was his next opponent, but if the Spaniard were to beat Shapovalov and win one more match, the No. 1 spot in the Emirates ATP Rankings would be his for the first time in more than three years, since 6 June 2014.

The Spaniard started quicker, breaking routinely in the eighth game. Shapovalov, though, swung freely in the second set, attacking with his forehand to even the match. Both players held throughout the third, so they headed to one of the most dramatic moments in tennis: a third-set tie-break.

Nadal cruised to a 3/0 lead and looked as if he would finally pull away. But Shapovalov rallied, crushing another forehand winner on match point before falling to the ground in shock. He embraced Nadal at the net before kissing the court and blowing kisses to his thousands of red-and-white clad admirers in the crowd.

The Canadian became the youngest Masters 1000 quarter-finalist (since 1990) and the lowest-ranked player to reach a Masters 1000 quarter-final since No. 239 Ivo Karlovic at 2011 BNP Paribas Open. It had been 13 years since a player younger than the 18-year-old Shapovalov had beaten a Top 2 player during a completed match. Nadal, 17, beat No. 1 Roger Federer at the 2004 Miami Open presented by Itau.

Shapovalov would go on to beat France's Adrian Mannarino and reach the Masters 1000 semi-final, where he fell to eventual champion Alexander Zverev of Germany. The 18-year-old Shapovalov also became one of seven 21-and-under players to qualify for the inaugural Next Gen ATP Finals in Milan.

(1) Evgeny Donskoy d. Roger Federer 3-6, 7-6(7), 7-6(5) – Dubai Duty Free Tennis Championships Third Round

Roger Federer had been perfect. The 36-year-old had shocked everyone and won seven straight matches to win his first tournament in six months, the Australian Open, beating four Top 10 players, including Rafael Nadal in the final, to capture his record 18th Grand Slam title.

A month later, Federer headed to Dubai, where it looked like his successful comeback from knee surgery would continue. The Swiss right-hander had won seven titles and 10 consecutive matches in the United Arab Emirates. After beating Frenchman Benoit Paire, Federer faced World No. 116 Evgeny Donskoy in the third round.

Federer rolled through the first set and held match points at 6/4 and 7/6 in the second set tie-break. He was a swing away from making the quarter-finals.

But Donskoy fought them off and forced a third set. Surely, though, Federer would rebound in the third.

Federer broke in the sixth game and served for the match at 5-4. But again, Donskoy, who hadn't reached a quarter-final since Moscow 2015, broke one of the greatest players of all time, and in the tie-break, the Russian delivered his best of the match.

Federer was in control at 5/2 with two serves to come. But in one of the wildest tie-breaks of 2017, World No. 116 Donskoy reeled off the final five points to prevail in just over two hours and pull off the biggest upset of the 2017 season. “I surprised everyone today,” Donskoy said.

Federer perhaps summed up best what his fans were thinking on the day his perfect season ended. “I don't know how it got away,” he said. “So many chances, it was crazy.”