Medvedev had said he did not like playing Tien after a trilogy of matches that went the distance last year and the 20-year-old American proved him right with a clinical performance that included 33 winners.
Germany's Alexander Zverev remained on track for a return to the Australian Open final after beating American Learner Tien 6-3, 6-7(5), 6-1, 7-6(3) in the Melbourne Park quarter-finals on Tuesday.
Learner Tien became the youngest man to reach the Australian Open fourth round in 20 years
Learner Tien is the youngest American man to reach the third round of the Australian Open since an 18-year-old Pete Sampras in 1990.
Defending champion Jannik Sinner, who has been recovering from illness, received a more favourable route to the US Open final than Carlos Alcaraz while Aryna Sabalenka will be tested in her bid to retain her title after the draw was made on Thursday.
Gauff is a fan favourite in Melbourne
As he chases Grand Slam success, Alexander Zverev describes the unseen routines and discipline behind playing tennis with type 1 diabetes.
World number two Jannik Sinner survived a stern test from Joao Fonseca on Tuesday to reach the Indian Wells quarter-finals.
Travel disruptions following airspace closures in the Gulf have forced Daniil Medvedev and Andrey Rublev to miss an Indian Wells exhibition, while an ATP Challenger in Fujairah was cancelled amid security concerns.
Carlos Alcaraz and Aryna Sabalenka advanced to the semifinals of the Indian Wells tournament, along with Daniil Medvedev and Elina Svitolina, after a series of compelling matches.
Australian Open organisers invoked their extreme heat policy as temperatures soared at Melbourne Park on Tuesday, prompting the suspension of play on outer courts and the closure of roofs on the main showcourts.
Sinner will face 19-year-old Learner Tien for the title.
IMAGES from Day 1 of the US Open matches played at Flushing Meadows, New York on Sunday.
Wimbledon: N Sriram Balaji enters second round in men's doubles
World No 1 Aryna Sabalenka fended off a serious challenge from Anastasia Potapova to reach the fourth round of the Australian Open.
India's Yuki Bhambri, along with his New Zealand partner Michael Venus, stormed into the men's doubles pre-quarterfinals at the US Open 2025
Fritz, Shelton lead American charge at US Open with first-round wins
Inspired American teenager Learner Tien outlasted three-times Australian Open runner-up Daniil Medvedev to reach the third round
The Russian, 28, whacked his racket into the net five times as his frustration boiled over during his opening victory against Thai wildcard Kasidit Samrej on Tuesday.
IMAGES from all the action on Day 8 of the Australian Open in Melbourne on Sunday.
Dhakshineswar, who is in US College circuit, could not qualify for the singles main draw, falling in the second round of the qualifying event 3-6, 4-6 to American fourth seed Learner Tien.
Carlos Alcaraz said he thought the trio of teenagers who have lit up the first week of the Australian Open have the skills to play the game at the top level
Michelsen, seeded 26th, will face hard-hitting 11th seed Karen Khachanov of Russia, who upset eighth seed Casper Ruud in their fourth round match 6-4, 7-5.
Coco Gauff forgot to bring her rackets to the court but reminded her rivals of her French Open title ambitions with a commanding win while Daniil Medvedev lost his composure on a cold and blustery Tuesday as he crashed out in the opening round.
Images from Day 7 of the 2025 Australian Open at Melbourne Park on Saturday.
Safiullin upsets Muller, Moutet through in Mallorca
Daniil Medvedev destroyed his racket and a net camera in a mid-match meltdown as he survived a huge scare against Thai wildcard Kasidit Samrej.
Jannik Sinner overcame a debilitating medical episode as well as Dane Holger Rune to reach the quarter-finals of the Australian Open for the third time.
Raducanu stormed into the third round of the Cincinnati Open