Simona Halep felt the need to apologise to her fans after she was swept aside by Garbine Muguruza in the Western and Southern Open final on Sunday.

The Romanian had the chance to become the WTA's number-one ranked player with victory in Cincinnati, but she was blown away by a devastating performance from the Spaniard, who romped to a 6-1 6-0 success in less than an hour.

It was Halep's third missed opportunity to ascend to the rankings summit this season, and the 25-year-old posted on Twitter to say sorry to her supporters for her disappointing display.

"Thank you Cincinnati for this great event. It's been a good week for me with [a] few good matches," she wrote.

"I want to apologies [sic] to the fans for the last match, I'm really disappointed but it is made by me so I take it BUT congrats to Garbine for the great tennis.

"I will keep myself working to get stronger on each side of myself.

"Thanks to my [team] that is by my side also in these moments, sometimes, like today, I can't respond even to [coach] Darren's [Cahill] advices.

"Looking forward to US Open now! See you soon."