Mark Edmondson's Australian Open triumph is widely considered to be the greatest Grand Slam shock of all time.
Edmondson defeated legend Ken Rosewall in the semi-final and reigning champion John Newcombe in the final to become the lowest-ranked Grand Slam winner, a record that remains today.
It would be seven-time Slam winner Newcombe's last final and Edmondson's only final. Surprisingly, Edmondson remains the last Australian to win their domestic Slam.
At 25/1 in 888sport tennis betting odds, it would be a shock if Nick Kyrgios could win in 2019, but not quite on the level of Edmondson's victory.
Goran Ivanisevic had only entered the 2001 Wimbledon tournament courtesy of a wildcard, a slump in form seeing him plummet down the rankings.
That wildcard was given because Ivanisevic had made the final on three occasions. The Croatian made the most of his opportunity, denying Tim Henman in an epic semi-final before battling past Pat Rafter to seal an overdue Slam title.
It's one thing for a 16-year-old qualifier to hold their own against the No. 1 seed in the first round of a Grand Slam. It's another thing entirely to dispatch of them with consummate ease, and yet this is what Jelena Dokic achieved against Martina Hingis in 1999.
Dokic only secured one Grand Slam semi-final in her career in comparison to Hingis' five titles but, for one day, in 1999 she was completely superior to the best player in the world.
Rafael Nadal's defeat to Dustin Brown in 2014 continued an unlikely trend for the two-time Wimbledon champion, losing to a player ranked outside the top 100 for the fourth consecutive year.
Being the fourth shock perhaps makes this match the least surprising, but Brown's style of play makes it the most memorable.
The maverick German plays like no other, a combination of ludicrous artistry and athleticism. Nadal's run of shock defeats makes him relatively unfancied to win his third Wimbledon title in 2019.
Kuerten began the 1997 French Open ranked 66 in the world, so few were backing him to win the tournament.
A more likely candidate was reigning champion Yevgeny Kafelnikov triumphing again, but Kuerten saw him off in a topsy-turvy quarter-final that was the Brazilian's third consecutive five-setter.
Kuerten then beat qualifier Filip Dewulf in the most unlikely of semi-final match-ups before taking down 16th-seed Sergi Bruguera to win his first of three French Opens.
Nadal's domination of the French Open market in recent years has been curtains for those seeking to emulate Kuerten.
*Odds subject to change - correct at time of writing*