Sofia Kenin’s emotional Australian Open defence ended in a second-round defeat Thursday but top seed Ashleigh Barty overcame a blip to reach the last 16.

The highly-strung Kenin has struggled to handle expectations in her first Grand Slam title defence and admitted to having a few tears during a tense opening-round win on Tuesday.

The fourth seed shed more on Margaret Court Arena Thursday after her 6-3, 6-2 defeat in 64 minutes to the Estonian world number 65, becoming the highest-ranked player to go out of the tournament.

“I felt like I wasn’t there, my head wasn’t there,” a teary-eyed Kenin admitted later.

A strong-serving Kanepi proved a bad match-up for Kenin, who had 22 unforced errors and offered little resistance as her title defence ended with a whimper.

Kanepi, however, has been in strong form, finishing runner-up in the warm-up Gippsland Trophy followed by a straight-sets victory over Latvia’s Anastasija Sevastova in the Open’s first round.

The 35-year-old plays 28th seed Donna Vekic of Croatia next.

Meanwhile world No 1 Barty cast friendship aside with a straight-sets victory over compatriot Daria Gavrilova, but appeared to lose focus serving for the match before closing out for a 6-1, 7-6 (9/7) win against her Fed Cup teammate.

Barty’s left thigh was heavily strapped but she seemed to move with ease in the second-round encounter against 387th-ranked Gavrilova.

Playing under an open roof at Rod Laver Arena in muggy conditions, she quickly found her stride and hit back immediately to peel off six games on the trot. But she unexpectedly slumped at 5-2 in the second set, dropping serve twice, and needed to save two set points in the tiebreaker before finally snuffing out Gavrilova.

Gavrilova once held the mantle of Australia’s number one before relinquishing to Barty, who has now won four of their five matches.

Barty, who made the semi-finals at last year’s Australian Open, plays 29th seed Ekaterina Alexandrova of Russia or Czech Barbora Krejcikova.

Ukrainian fifth seed Elina Svitolina scored an efficient 6-4, 6-3 win over 16-year-old Coco Gauff.

The American teen, who had knocked out Venus Williams and Naomi Osaka on her way to the fourth round last year, was unable to replicate the success against the efficiency of the veteran. But Svitolina’s experience came to the fore in the pivotal moments of the free-wheeling contest.

Svitolina’s precise hitting overcame the dangerous Gauff, who showed flashes of the form that fuelled her dazzling run last year at Melbourne Park, but she lacked the consistency of her hardened opponent.

The 16-year-old’s thunderous serve kept her in the hunt during a high-octane first set, but she eventually cracked against Svitolina’s unnerving accuracy. The seed then withstood a barrage of heavy groundstrokes from the American to grind out the victory in straight sets.

Sixth seed Karolina Pliskova of the Czech Republic had few alarms in beating American Danielle Collins, a semi-finalist at Melbourne Park two years ago, 7-5, 6-2.

Swiss 12th seed Belinda Bencic was pushed harder by veteran Russian Svetlana Kutznetsova before coming through 7-5, 2-6, 6-4 in 2hr 39min.

Results

Ashleigh Barty (AUS x1) bt Daria Gavrilova (AUS) 6-1, 7-6 (9/7)

Ekaterina Alexandrova (RUS x29) bt Barbora Krejcikova (CZE) 6-3, 7-6 (7/4)

Anett Kontaveit (EST x21) bt Heather Watson (GBR) 6-7 (5/7), 6-4, 6-2

Shelby Rogers (USA) bt Olga Danilovic (SRB) 6-2, 6-3

Belinda Bencic (SUI x11) bt Svetlana Kuznetsova (RUS) 7-5, 2-6, 6-4

Elise Mertens (BEL x18) bt Lin Zhu (CHN) 7-6 (10/8), 6-1

Karolina Muchova (CZE x25) bt Mona Barthel (GER) 6-4, 6-1

Karolina Pliskova (CZE x6) bt Danielle Collins (USA) 7-5, 6-2

Kaia Kanepi (EST) bt Sofia Kenin (USA x4) 6-3, 6-2

Donna Vekic (CRO x28) bt Nadia Podoroska (ARG) 6-2, 6-2

Jennifer Brady (USA x22) bt Madison Brengle (USA) 6-1, 6-2

Kaja Juvan (SLO) bt Mayar Sherif (EGY) 3-6, 7-6 (7/2), 6-3

Jessica Pegula (USA) bt Samantha Stosur (AUS) 6-0, 6-1

Kristina Mladenovic (FRA) bt Nao Hibino (JPN) 7-5, 6-1

Yulia Putintseva (KAZ x26) bt Alison Van Uytvanck (BEL) 6-4, 1-6, 6-2

Elina Svitolina (UKR x5) bt Coco Gauff (USA) 6-4, 6-3

With AFP Inputs