Hobbling Juan Martin del Potro and Polish trailblazer Jerzy Janowicz hope to derail the Wimbledon title dreams of Novak Djokovic and Andy Murray, the world's two best players, in Friday's semi-finals.
Del Potro, the 2009 US Open champion, just about survived his quarter-final against David Ferrer when he strained his already heavily-bandaged left knee in a sickening Centre Court tumble.
The giant Argentine now tackles world number one and Australian Open champion Djokovic.
Janowicz, the first Polish man in the last-four of a major, takes on US Open and Olympic champion Murray who is bidding to be the first British man in 77 years to win Wimbledon.
Djokovic has an 8-3 winning record over Del Potro but the Argentine won their only other previous meeting on grass in the 2012 Olympics bronze medal play-off which took place at Wimbledon.
Del Potro also won the pair's last meeting in March, on hard court in the Indian Wells semi-finals.
But Djokovic, having escaped the shock exits suffered by the likes of Roger Federer and Rafael Nadal at this year's Wimbledon, believes that he can still play better.
"It's the mindset I always try to have, because that's something that keeps me going every single day on the practice courts, day in, day out, trying to give my best and trying to always inspire myself to play better tennis," he said.
"I know I have a quite complete game, but I still feel there is room for improvement."
The Serb, the 2011 Wimbledon champion, will be playing in his 13th successive Grand Slam semi-final, 10 behind the record held by Federer.
At Wimbledon this year, he is chasing a seventh major.
Top seed Djokovic won't be lulled into a false sense of security by the injury-cursed Del Potro's latest problems.
The 24-year-old eighth seed is used to tackling physical problems.
In 2010, he played just three tournaments and saw his ranking slip to 257 in the world after undergoing wrist surgery.
