WASHINGTON, DC, USA - Jessica Pegula came from a set and a break down to move into her second Citi Open quarterfinal, defeating teenage phenomenon Iga Swiatek 5-7, 6-4, 6-1 in two hours and 19 minutes.

Swiatek had recovered a set and a double break deficit for a win over Ons Jabeur in the first round, and for a while it seemed as though the 18-year-old would pull off another Houdini act after roaring back from 2-5 down in the first set - saving three consecutive set points at 4-5 - to take a 7-5, 2-0 lead. But in the end it was Pegula who would take the comeback honours, gathering herself to prove the more solidly aggressive player throughout the home stretch and seal a place in her first quarterfinal of 2019.

"I came out really fast - I think I caught her off guard," assessed Pegula afterwards. "Then I was on my back heels a little bit [when she came back] -  but I knew if I could just push through and stop the bleeding then I could come back, and that's what happened."

The American had begun brightly, unleashing on her forehand and swarming the net to keep Swiatek on the run and off balance. An emphatic smash captured the first break in the second game, and Pegula would ride that momentum to a 5-2 lead.

But though the Pole had taken some time to find her groove, once she did she began to counter Pegula's strategy effectively. Anticipating the 2016 semifinalist's net forays more sharply, Swiatek began to nail her passes as she gradually climbed back into the set. Pegula wobbled serving for it with a double fault and suddenly-errant forehands - and although Swiatek nearly repaid her in kind in the subsequent game, clutch serving dug her out of a 0-40 hole before the World No.66 swept through to steal the set, aided by another pair of double faults from a collapsing Pegula.

By now, the 25-year-old was losing all of the mental battles - and when she squandered four game points to concede her serve in a 10-minute mini-epic at the start of the second set, the pattern continued. But it was another mini-epic that turned the match for Pegula: two games later, she would snap a seven-game losing streak and fend off three points to go down a double break, and get her reward with an immediate break back to level at 2-2.

Pegula was not quite out of the danger zone yet - the final stretch of the second set would be full of such tussles, and she would have to retrieve another break as Swiatek moved ahead 4-2. But by now, the Québec City runner-up was firmly back in the match game-wise, attacking her opponent's second serve with relish and scoring a number of brilliant strikes from both wings. Swiatek, by contrast, was struggling for consistency: the Lugano finalist showed off some superb reflex winners throughout the match, but her insistence on taking the ball as early as possible also resulted in a number of errors as Pegula's deep returns caught her out.

Having ground out a 5-4 lead in the second set, Pegula pounced: a brace of booming backhand returns put her in the driver's seat, and a rattled Swiatek coughed up a double fault facing set point. The deciding set would be closer than the scoreline suggests, with both players alternating between spectacular shotmaking and wild errors: four of the seven games would go to deuce. However, in contrast to the first set, it was Pegula who was demonstrating superior confidence and control: the World No.79 won all of those deuce tussles, with Swiatek's unforced errors looming even larger when game point or break point down.

With a series of poor dropshots from the teenager providing even further encouragement, Pegula would ultimately come through 10 of the final 11 games, closing the match out with consecutive service winners to set up a quarterfinal against either No.4 seed Sofia Kenin or 2016 runner-up Lauren Davis - Pegula's own semifinal conqueror that year.