US Open fourth round tips: Tien's roll meets Khachanov's revival

The US Open fourth round sends Karen Khachanov up against Learner Tien at 4:00 am AEST on Tuesday, and the form ledger tells two different yarns. The Russian is ranked 50th in the world and sits 39th in the ATP points ladder; the 15th-ranked American has momentum on his side with four wins on the trot. Both men won their third-round matches, but the paths that brought them here couldn't be more different.

Khachanov's season has been stop-start — a 19–18 record overall, no titles, and a recent patch that saw him drop two of three before his latest win. Tien, meanwhile, has already banked a title this year and boasts a 66 per cent win rate across 29 victories. The head-to-head ledger is blank; they've never met on tour. That makes the current market price the only guide punters have, and the bookies have Tien a clear favourite at the shorter quote.

Who will win? Tien's hot hand against Khachanov's restart button

Learner Tien is coming off a straight-sets win over Nuno Borges on Tuesday, 1 September — his fourth straight victory. That run includes wins over Thiago Agustin Tirante, Tommy Paul, and a dominant performance that featured a 6–0 set along the way. The last five starts show four wins and one loss, all fought out across hard courts and grass. The American's 29–15 season record and career 71–45 mark tell you he knows how to close out matches.

Karen Khachanov's last start was also a win — a straight-sets dismantling of Roman Andres Burruchaga on the same date — but the context is shakier. Before that, he'd dropped two on the bounce, and his last five overall reads one win, two losses. The Russian's career numbers (333–245, 58 per cent) dwarf Tien's, but form is a fickle beast, and right now the younger man has it in spades.

The rankings paint the picture: Tien sits 15th in the live ATP order with 2,155 points; Khachanov is ranked 50th with 1,130. On current prices, the market leans heavily toward the American, and the form line backs that up. Tien has won four straight; Khachanov needed his third-round win just to stop the rot.

Sets Handicap: can Khachanov make it a scrap?

The Sets market has Khachanov at plus-2.5 sets — in other words, the Russian gets a 2.5-set start on the handicap. That's a hefty cushion, and it reflects the market's view that Tien is the better player on the day but might not cruise in straights. Khachanov's last win was a tidy three-setter, and he's shown in the past that he can hang with higher-ranked opposition when his serve fires.

Tien's recent wins have been clinical — three of his last four were straight-sets affairs, and even the one that went longer saw him dominate the deciding frame. If the American keeps that level, Khachanov will struggle to pinch a set, let alone two. The +2.5 cushion is there for a reason: the market expects Tien to control proceedings but leaves room for the Russian to avoid the bagel treatment.

The yarn: youth and momentum trump experience

This one comes down to which story you buy: the veteran with seven career titles and 333 match wins trying to rediscover his mojo, or the 19-year-old left-hander riding a four-match streak into the second week of a Slam. Khachanov has the pedigree — he's been as high as eighth in the world — but pedigree doesn't win matches when the wheels are wobbling. His 19–18 season and recent losses suggest he's fighting his own game as much as his opponent.

Tien, on the other hand, is playing with house money. The American has already banked a title this year and sits comfortably inside the top 20. His 66 per cent win rate this season is elite, and his last five starts show he's peaking at the right time. The market has him favourite for a reason, and the form ledger doesn't lie. When you're weighing up your tennis tips, the momentum angle is hard to ignore here.