ACAPULCO, Mexico - No.7 seed Heather Watson advanced to her second quarterfinal of the season on Wednesday at the Abierto Mexicano Telcel presentado por HSBC by virtue of a 7-6(2), 6-2 victory over Ukraine's Kateryna Bondarenko.
In the pair's fifth meeting, a competitive first set that lasted over an hour allowed the British No.2 to ultimately seal a second round victory in one hour and 45 minutes.
From 3-1 up in the first set, the No.7 seed lost four straight games, and found herself staring at the prospect of a one-set deficit for the second match running in Mexico -- and also had another pressing concern on her own side of the net.
"I felt like this match was a lot more physical [than the first round]," Watson said. "We had a lot of longer points, and I think by the end, we were both pretty worn out physically.
"At 3-1 in the first set, I felt like I was playing really good, feeling the ball well. At 15-0, I hit a backhand return, and I landed funny and felt my knee a bit, and I lost the next four games.
"I was even thinking, 'I don't know am I going to finish this match.' As the match went on, I started to get a better feeling in my knee, more trust in it, and it was a battle by that stage."
Unlike in her first match, where she rallied from a set down to beat former Top 10 player CoCo Vandeweghe in a tight three-setter, Watson ultimately battled back, and saved two set points, on her road to a straight-sets victory.
After Watson broke Bondarenko in the ninth game to get the set back on serve, a titanic service game ensued before the Brit ultimately leveled the set at 5-5. She saved a pair of set points in a game that went to deuce six times, before ultimately leveling the set at 5-5.
Though she failed to serve out the set after riding that momentum into a fourth break of serve and a 6-5 lead, Watson dominated from 1-1 in the tiebreak to seal the overall lead.
"I did really well to save those set points in the first set in that really tight game, and I played a really good tiebreak," the No.7 seed added.
"Once I got through that, I felt like I had momentum and I could release more in my strokes. I was really pleased with that second set, especially because it was such a physical match in these conditions.
"It was a good test of my fitness and my mental toughness today."
Watson was quick out of the gates in the second set, as she won the first three games at a canter and never was under threat to trail from then on. She dropped just four points across four service games in the set overall, and despite failing to convert a break point to lead 4-0, she ultimately scored a second break to win the match.
"I think it was momentum, but I went for my shots more in the first game," Watson said of the second set. "I hit an ace and a good backhand down the line, and that gives you confidence.
"She maybe felt like she had to go for more, and started missing a few, so it's all a domino effect."
After losing the first two matches against Bondarenko in a head-to-head that dates back to 2015, Watson has now won the last three -- including two in the past six months since the Ukrainian returned to the WTA after the birth of her second child last year.
"I know that Kateryna is a really tough player. She's very aggressive, and I just played her recently at the end of last year," Watson said.
"I knew what to expect, and she's playing a lot better now, so she's a very dangerous opponent. I'm just pleased with how I stuck to it."
Watson totaled 20 winners and 20 unforced errors in an even performance, as she never faced a break point in the second set after dropping serve four times in the first set. Conversely, Bondarenko balanced out 33 unforced errors with just 17 winners, and also totaled nine double faults -- two of which came in the match's final game.
Up next, Watson is guaranteed to face another American with a spot in her second semifinal of the season on the line, in either qualifier Caroline Dolehide or Christina McHale.
"They're both very good players. They both have heavy balls. Caroline has a good kick serve and Christina has a heavy forehand," Watson said.
"Christina is a good friend of mine. We're the same age, we came through juniors together, and we've been on the same journey since we were very young. Whoever I play, it's going to be a tough match."
In other British interests, Katie Boulter's tournament ended at the hands of China's Zhu Lin in straight sets, 7-6(2), 7-5. The former World No.82, who missed six months of 2019 with a back injury shortly after reaching her career-high ranking, earned her first WTA main draw victory in exactly a year over American lucky loser Francesca Di Lorenzo in the first round.