Elena Rybakina says she is motivated by world number one race but taking things day by day after US Open win

Elena Rybakina says she is "motivated" by the race to become world number one but is simply taking things "day by day" after getting her US Open campaign off to a winning start.

Playing for the first time since withdrawing midway through her Cincinnati Masters quarter-final with a heel injury last month, Rybakina showed no signs of discomfort as she eased to a dominant 6-3 6-2 win over 17-year-old wildcard Thea Frodin.

The 27-year-old second seed trails Aryna Sabalenka by just 434 points in the world rankings and will become number one for the first time by reaching the semi-finals in New York – even if Sabalenka defends her title.

Regardless of her performance, Rybakina will also secure the top ranking if none of Sabalenka, Coco Gauff and Jessica Pegula lift the trophy.

"I'm definitely motivated [to become world number one]," said Rybakina, who trailed Sabalenka by more than 3,000 points in the spring before the Belarusian entered a mid-season slump.

"I feel like I had opportunities before and it didn't go my way. It will be an amazing achievement but it's still too far and I need to focus on my day off tomorrow, my recovery, and just keep on going."

Rybakina, a two-time Grand Slam winner, arrived at Flushing Meadows with question marks around her fitness after retiring injured against Iga Swiatek in Cincinnati.

Though she looked comfortable on court, her movement went largely untested by Frodin - who acted as Serena Williams' body double in the Oscar-nominated film 'King Richard' - as she blew the world number 585 away on serve and dictated points from the baseline.

"We didn't know if [I was] going to be able to play here or not. I'm pretty happy that I'm playing right now, and we are taking [it] day by day," Rybakina said about her injury.

"I was not playing for the full week [before the tournament], so seven days no tennis and basically not too much gym I could do movement-wise.

"So it's a great result after 10 days from that kind of injury."

After opening the rain-delayed match with a double fault, Rybakina proved relentless on serve, dropping just three points and reeling off three consecutive love holds in the first set.

She didn't face a break point until the sixth game of the second set, saving both.

Equally clinical in Frodin's service games, she converted her first three break points to race into a set and 5-1 lead.

However, the young wildcard, making her WTA Tour main-draw debut after winning the United States Tennis Association (USTA) Girls' 18s National Championship, made Rybakina work to get over the line, saving three match points with aces in her final service game among 11 across the match.

Rybakina served out the win with an ace of her own – her sixth of the match and a tour-leading 363rd of the season.

"She played really well today. She has great shots, great serve, it was no easy," Rybakina said of the largely unknown Frodin.