Youngster Learner Tien and veteran Gael Monfils defied their respective ages as both players qualified for the Australian Open fourth round.
American qualifier Tien, playing for the first time in the Melbourne main draw, earned a 7-6 (12-10) 6-3 6-3 win over France's Corentin Moutet.
The 19-year-old pulled off the shock of the tournament in the previous round with victory over three-time finalist and fifth seed Daniil Medvedev.
Tien had previously never been beyond the first round at a Grand Slam. He has now become the youngest man since an 18-year-old Rafael Nadal in 2005 to reach the men's singles last 16 at the Australian Open.
Frenchman Monfils, meanwhile, rolled back the years with a fabulous performance to earn a 3-6 7-5 7-6 (7-1) 6-4 win over American fourth seed Taylor Fritz.
The 38-year-old's win over US Open runner-up Fritz means he becomes the second oldest man since 1988 to reach the Australian Open fourth round.
- Roger Federer is the oldest in that time frame, having reached the semi-finals at Melbourne Park in 2020 aged 38 years and five months..
