US Open 2018: World No 1 Simona Halep beaten in first round by Kai Kanepi

Unseeded Kaia beat the world number one 6-2, 6-4, the second consecutive time Halep has lost her opening match at Flushing Meadows

Simona Halep has been beaten in the first round of the U.S Open for a second consecutive year (Getty)

This has been a memorable year for Simona Halep, but the world No 1’s Grand Slam season ended here on Monday with defeat in her opening match at the US Open. Smashing her racket and thumping balls away in anger, Halep was a picture of frustration as she was beaten 6-2, 6-4 in just 75 minutes by Kaia Kanepi, the world No 44.

Halep had seemed a changed woman after finally winning her first Grand Slam title at the French Open in June – she had lost in her three previous Grand Slam finals - but the self-confidence which followed that breakthrough appeared to evaporate on a steamy opening day at Flushing Meadows.

Early in the second set there was the rare sight of the 26-year-old Romanian pummelling her racket on the ground after losing a point and there were times when she smashed the ball away in frustration.

Halep is often beaten for power by her opponents, but her great athleticism and consistent ball-striking are usually more than adequate compensation. On this occasion, however, she had no answer to Kanepi’s thumping ground strokes.

Halep was frustrated in defeat (Getty)

Afterwards Halep had no excuses. “She started pretty well and pretty strong,” she said. “Actually, I expected her to play like that, without fear and hitting the balls really strong.I cannot say much about this match, just that I didn't really feel the ball. But she played really strong and pushed me back.”

It was a second successive first-round exit here for Halep following her defeat to Maria Sharapova 12 months ago, but this was a much greater surprise. Sharapova, who was rebuilding her world ranking following her 15-month suspension for a drugs offence, had beaten Halep in all six of their previous meetings, whereas Kanepi had lost to the Romanian in their only other encounter.

Nevertheless, two of Kanepi’s six Grand Slam quarter-final appearances have been in New York and the 33-year-old Estonian hit the ball confidently from the start.

Going for her shots, Kanepi made 28 unforced errors to her opponent’s nine, but the more telling statistic was the Estonian’s 26 winners, compared with only nine for Halep.

“I have always loved being in New York,” Kanepi said afterwards. “I like the atmosphere. I like being here. I love the courts and the climate, and I think that the courts suit my game really well.”

This was the first match in the new Louis Armstrong Stadium, which is the second of the main show courts here. The impressive new arena has an intimate feel to it and is the second court – after Arthur Ashe Stadium – to have a retractable roof. Nevertheless, it was never more than half full during the match.

Kanepi set the pace from the outset. Halep has made slow starts in the past, but when she went a set and 3-0 down her prospects looked bleak. The Romanian is a fighter, nevertheless, and with her supporters getting behind her with chants of “Simona! Simona!” she launched a spirited fightback.

Having already retrieved one break of serve, Halep levelled the score at 4-4, breaking Kanepi to love. The world No 1 had a point for a 5-4 lead, but Kanepi kept going for winners and went on to break serve for the fifth time in the match with a clever volley, upon which Halep slapped the ball away in anger.

Kanepi comfortably beat the World Number one in an hour and 14 minutes (Getty)

Serving for the match, Kanepi closed out her victory in confident style, forcing Halep back with a succession of big shots. Halep’s lead at the top of the world rankings is such that she is guaranteed to be No 1 at the end of the tournament, but for the moment that will be little consolation.

“I think every player struggles a little bit in the first round,” Halep said afterwards. “It's always about the nerves. Even when you are there at the top, you feel the same nerves. You are human. So it's the same thing.For me, it's more difficult in the first rounds, because I'm more emotional. That's why I need a good start.”

Halep said she rarely played her best tennis here. Asked why that was, she replied:“Maybe the noise in the crowd. The city is busy. So everything together. I'm a quiet person, so maybe I like the smaller places.But I’ve had great results here and I'm not complaining. I just say that I don't really feel 100 per cent my game when I step on the court here.”

Halep’s defeat could be good news for Serena Williams, who was playing Magda Linette later in the day. Halep and Williams were seeded to meet in the fourth round.

Garbine Muguruza has made an impressive start (Getty)

Heather Watson’s wait for a main-draw victory here will continue for another year after the Briton was beaten 6-1, 3-6, 6-3 by Russia's Ekaterina Makarova. It was Watson’s eighth successive loss in the first-round here, though it came after a promising upturn in the world No 116’s form during qualifying.

Makarova has a fine record in Grand Slam tournaments and quickly took command of the first set. Watson fought back well to recover from 3-1 down in the second set and level the match, but the Russian was the better player in the decider.

Garbine Muguruza, last year’s Wimbledon champion, made an impressive start, beating Shuai Zhang 6-3, 6-0, but Elina Svitolina was made to work for her first-round victory. Svitolina beat Sachia Vickery 6-3, 1-6, 6-1.