Jack Draper crashes out of Miami Open after loss to Reilly Opelka, while Ethan Quinn stuns Casper Ruud in a breakthrough win.
Rangy 19-year-old Mensik, the 2022 boy's singles finalist at Melbourne Park, sealed the match in style with a searing forehand winner to push the three-times Grand Slam finalist and sixth seed to the exit.
Norway's Casper Ruud won his first Masters 1000 title on Sunday, as he stormed to a 7-5, 3-6, 6-4 victory over fifth seed Jack Draper in the Madrid Open final with a gutsy performance that showcased his clay-court mettle.
Jack Draper stunned Novak Djokovic in a deciding-set tie-break while Carlos Alcaraz extended his winning streak to reach the quarter-finals of the Indian Wells Open. Iga Swiatek, Jessica Pegula and Elena Rybakina also advanced.
Ruud criticises ATP rankings 'rat race'
Jannik Sinner brushed aside heat concerns to reach the Australian Open quarter-finals, while Iga Swiatek ended home hopes by overpowering Maddison Inglis in Melbourne.
Norwegian Casper Ruud did not let a rib injury get in the way of setting up a Madrid Open final showdown with fifth seed Jack Draper as he reached the title match without dropping a set following a 6-4 7-5 win over Francisco Cerundolo on Friday.
Carlos Alcaraz suffered a shock 6-1, 7-5 defeat against Norway's Casper Ruud in his opening match at the ATP Finals
Norway's Casper Ruud, the French Open runner-up in 2022 and 2023, crashed out of the tournament in the second round on Wednesday after losing 2-6, 6-4, 6-1, 6-0 to unseeded Nuno Borges of Portugal.
The event comes at a time when tennis is facing criticism over its relentless tour schedule.
Factbox on Carlos Alcaraz, who beat Serbian fourth seed Novak Djokovic to win his first Australian Open title on Sunday, increasing his overall Grand Slam tally to seven.
Alexander Zverev cruised past Frenchman Lucas Pouille in straight sets in the first round of the Australian Open on Sunday.
Casper Ruud gained sweet revenge over Stefanos Tsitsipas as he beat the Greek fifth seed 7-5, 6-3 to win the Barcelona Open on Sunday.
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.
As the spotlight shines on Carlos Alcaraz's title defence and Novak Djokovic's pursuit of a record 25th Grand Slam, a determined group of challengers is quietly preparing to shake up the draw.
Novak Djokovic fights past Aleksandar Kovacevic to reach the last 16 at Indian Wells Open, setting up a clash with defending champion Jack Draper.
Casper Ruud stunned top seed Novak Djokovic 6-4 1-6 6-4 in a thrilling Monte Carlo Masters semi-final on Saturday, avenging his loss in last year's French Open final to set up a title clash with twice champion Stefanos Tsitsipas.
Italians Sara Errani and Andrea Vavassori retained their mixed doubles title at the US Open on Wednesday, overcoming Iga Swiatek and Casper Ruud in the final.
But Ruud, a semi-finalist last year, stamped his authority in the tiebreak and did not face a single break point in the match as he beat the Canadian for the second time this year.
The Dutchman collapsed on the court after converting his sixth match-point to end an absorbing three hour, seven minute affair under sunny skies on Stadium One court.
A 55-shot, marathon rally brought fans to their feet in Flushing Meadows on Friday but nearly leveled the two men who lived through it, Norwegian Casper Ruud and Russian Karen Khachanov, competing in their US Open semi-final.
The match marked world number two Medvedev's ninth win in a row at the ATP Finals and he improved his head-to-head record over Ruud to 3-0.
Eighth seed Casper Ruud rallied from a set down to beat an error-prone Marin Cilic 3-6, 6-4, 6-2, 6-2 on Friday to become the first Norwegian man to reach a Grand Slam singles final and set up a French Open title clash against 13-time champion Rafael Nadal.
'We heard it was like the Hollywood of mixed doubles.'
Casper Ruud has become the first Norwegian to book a place in the season-ending ATP Finals, leaving one spot to be filled at the tournament in Turin, Italy later this month.
He also overtook his career-best 65-season win tally of 2023 with this win.
Cilic had never made it past the quarters in Paris but has now made the semis or better at all four majors.
Casper Ruud returned to the French Open final for a second year running by dismantling German 22nd seed Alexander Zverev to set up a showdown with 22-times Grand Slam champion Novak Djokovic.
Despite all the trials and tribulations he suffered in the build-up, no one could prevent Nadal from lifting the Musketeers' Cup for a record-extending 14th time.
Norwegian Casper Rudd is the first tennis player from his country to reach the final of any Grand Slam.
Alexander Zverev kept his bid for an elusive first Grand Slam title alive by reaching a fourth straight semi-final at the French Open
Norway's Casper Ruud harnessed his mighty forehand to reach his second Grand Slam final this year by beating Russia's Karen Khachanov 7-6(5), 6-2, 5-7, 6-2 at the US Open, keeping alive his hopes of reaching the top of the world rankings.
World number one Novak Djokovic began his quest for a sixth title at the season-ending ATP Finals with a 7-6(4), 6-2 victory over Norway's Casper Ruud in their round robin encounter in Turin on Monday.
IMAGES from Day 3 of the Wimbledon Championships, at the All England Lawn Tennis and Croquet Club, London, on Wednesday.
An off-colour Alcaraz lost 6-1, 7-5 to Norway's Casper Ruud in his opening match on Monday and the 21-year-old cancelled a public training session the following day.
Iga Swiatek captured her first Cincinnati Open title on Monday by beating Jasmine Paolini in straight sets.
'When you are playing defensive against Rafa on clay, he will eat you alive'
The Dane revealed he had taken notes from how Novak Djokovic beat Alcaraz in the Olympic final at Roland Garros.
World number two Gauff clawed her way back from a set down to defeat Russian Veronika Kudermetova 4-6, 7-5, 6-2 in a match that stretched over two and a half hours.
Defending ATP Finals champion Novak Djokovic has pulled out of the season-ending event in Turin through injury, the Serbian said on Tuesday.