Sensing some serious chinks in Rafael Nadal's Wimbledon armour, former champion Pat Cash believes Nick Kyrgios has the game to genuinely trouble the tennis world No.1 in the fourth round.
Australian teenager Kyrgios continued his dream Wimbledon debut by defeating 68th-ranked Czech Jiri Vesely 3-6 6-3 7-5 6-2 in the third round.
In doing so he set up a last-16 showdown with 14-time major champion Nadal on Wednesday, a match held over an extra day due to rain delays and likely to be played on the All England Club's famed Centre Court.
Kyrgios is bidding to become the youngest man to reach the Wimbledon quarter-finals since compatriot Bernard Tomic in 2011 and the first man to make the last eight on debut since Florian Mayer in 2004.
The wildcard Australian, ranked 144th and the at 19 the youngest man in the draw, believes anything is possible but a win would rank among the biggest upsets in Wimbledon history.
However Australian Cash, the 1987 champion, wouldn't be surprised to see big-hitting Kyrgios take a set or two off Nadal, who has lost the first set in all of his three matches so far.
Two of Nadal's majors have come at Wimbledon, in 2008 and 2010, but in recent years he's looked most vulnerable on grass - reaching the last 16 this year for the first time since 2011.