Kevin Anderson will face 9th seeded Austrian, Dominic Thiem, for a place in the US Open quarter-finals in New York later on Sunday.
The 5th seed South African, who reached the final in 2017, has won six of their seven previous outings.
Meanwhile, German veteran, Philipp Kohlschreiber caused a huge third-round upset when he beat his 4th seeded compatriot, Alexander Zverev.
Zverev won the first set tie-break but it was all downhill from there.
An out-of-sorts Zverev made 52 unforced errors and converted only three of 13 break-point opportunities.
Kohlschreiber, however, made the most of his opponent’s mistakes and recorded a 6-7, 6-4, 6-1, 6-3 win.
To book a fourth-round date with 21st seed, Kei Nishikori of Japan.
Philipp Kohlschreiber says:”I think it was a really entertaining match. You have Sasha with the big serve, the big stroke and my variety of the game today worked out perfect. Of course I’m very pleased with my performance.”
The 2nd seed, Roger Federer, of Switzerland was also in fine form against temperamental Australian, Nick Kyrgios.
Federer’s shot-making left Kyrgios speechless at times.
And the Swiss legend eventually managed a straight-sets win in an hour and 45 minutes.
Other third-round winners included Novak Djokovic of Serbia, and 7th seeded Czech, Marin Cilic.
Cilic outlasted another Aussie, Alex de Minaur in an epic five-setter that lasted four hours.
In the women’s draw, Maria Sharapova of Russia also advanced to the last 16.
Sharapova recorded a comfortable 6-3, 6-2 win over former French Open champion, Latvia’s Jelena Ostapenko.
Maria Sharapova :”She’s a phenomenal player and she’s a grand slam champion and I can’t come out here and expect an easy match. I think that’s what got me going, that competitiveness, knowing that we did play over 3 hours just months ago and that speaks a lot of her game.”
But former grand slam champions, 4th seeded German, Angelique Kerber and 5th seeded Czech, Petra Kvitova were sent packing.
Kerber lost in three sets to diminutive Dominika Cibulkova of Slovakia, while Kvitova suffered a straight-sets loss to Belarus’ Aryna Sabalenka.