Serena Williams moved within one win of a second pre-US Open hardcourt title on Saturday, reaching the Cincinnati Masters final with a 2-6 6-2 6-4 victory over Caroline Wozniacki.

The world No.1 American, who claimed her 61st career title at Stanford two weeks ago, will face off on Sunday against either fifth-seeded Maria Sharapova or ninth-seeded Ana Ivanovic.

Williams, playing a third tournament in a row for the first time since late 2007, improved her 2014 match record to 37-6.

The 32-year-old said that she needed a set to find her game after a slow start in a match which featured 15 breaks of serve, seven of them in the final set.

“I was feeling tired today, so in the second set I just told myself to hit big serves,” said Williams, who followed up her win in Stanford by reaching the semi-finals last week at Montreal, where she lost to her sister Venus.

“I didn’t expect to do this well over the summer. I knew I needed matches so I entered three tournaments. But I’m still here.”

Wozniacki entered the match after beating two top 10 players in a row – Angelique Kerber and Agnieszka Radwanska – for first time since the 2010 WTA Finals.

Wozniacki, who lost to Williams in three sets in the Montreal quarter-finals, won the opening set in half an hour despite double-faulting away a service game.

But Williams stepped up a gear in the second, helped to an early break by another of Wozniacki’s double faults.

The third was a roller-coaster for both players, who are good friends off the court.

After five straight breaks of serve, Williams finally stopped as she held for a 4-2 lead.

She secured another break for 5-2 but then had to face a Wozniacki fightback, with the former number one reaching 4-5.

Williams finally closed it out in the next game after a game later after an hour and three-quarters. She finished with seven aces and benefitted from eight Wozniacki double faults.

“I knew I had to return better, and today I was able to do that,” Williams said.

“I actually felt better than in my other matches.”