There is more to Madison Keys than just power.
The American 19-year-old showed character and courage in her maiden grand slam quarter-final on Wednesday.
Keys battled past idol Venus Williams, despite a left adductor injury threatening to derail her Australian Open.
Just like most of the WTA Tour's up-and-comers, Keys possesses incredible power off both sides.
But more than that was needed on Rod Laver Arena, and she showcased it in tough moments.
Keys was twice down a break in the deciding set – including trailing 3-1 – before fighting back.
Breaking Venus' serve to love in the 10th game saw her into her first grand slam semi-final.
Venus regularly tested her movement, particularly to the backhand side that appeared sore.
But she responded and, even with the pressure on, hit freely to claim victory.
Serena, battling a virus, is her semi-final opponent.
The numbers point to an enthralling, power-hitting duel.
Aces
Serena 57 – ranked #1
Keys 30 – ranked #2
Service games won
Serena 41/50 (82 per cent) – ranked #5
Keys 44/56 (79 per cent) – ranked #T10
Return winners
Serena 29 – ranked #1
Keys 17 – ranked #4
Total winners
Serena 170
Keys 123
Fastest serves
Serena 204 km/h – ranked #1
Keys 196 km/h – ranked #4
Keys has defied her 19 years throughout the tournament, which has included an upset win over Wimbledon champion Petra Kvitova.
The 2015 tournament may be too soon for her.
If she can hold her nerve, Keys' power and character is capable of testing Serena – who is battling illness.
But just how sore that adductor is after a 24-hour turnaround may prove her biggest test.
The 18-time grand slam champion that is Serena is also approaching some of her best form, making her extremely difficult to beat in the latter stages of a major.