Elina Svitolina said the Ukraine flag in the crowd "really helped" her to victory as she progressed to the quarter-finals of the Monterrey Open with a 7-6(3) 3-6 6-2 win over Viktoriya Tomova.
The Ukrainian top seed won in two hours and 24 minutes in Mexico to set up a last eight match against Colombian fifth seed Camila Osorio.
Svitolina, who won the Monterrey title in 2020, trailed 2-0 in the final set before winning the final six games to progress.
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The 27-year-old said afterwards: "It was an extremely tough first set, second set didn't go my way, and then the third set I was 0-2 down. I was not playing my best, but I was fighting, until the very end.
"And you know, the Ukrainian flag [in the crowd] really helped me today to fight... I was really fighting until the end, and I found my game in the end."
Britain's Heather Watson was knocked out in the last 16, losing 6-4 7-6(2) to sixth seed Nuria Parrizas-Diaz.
Wang Qiang defeated Mayar Sherif 6-0 6-7(2) 6-3 and Marie Bouzkova beat Petra Martic 6-4 6-2.

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Earlier on Wednesday, Ukrainian wildcard Dayana Yastremska said she was able to better control her emotions after progressing to the quarter-finals of the Lyon Open with a 6-2 6-3 win over Spanish qualifier Cristina Bucsa.
Yastremska admitted to Eurosport that she has struggled to deal with her emotions on the court with her war-torn country suffering greatly.
She had to save two match points in her opening round match against Ana Bogdan before winning in three sets, but had an easier ride against Bucsa, winning 68% of her points on the Spaniard's second serve, and said she is happy to be safe in France with her sister Ivanna after the siblings fled Ukraine.
"Today definitely was a little bit easier with my emotions," said Yastremska.
"I could keep them under control, so I’m very happy with that.
"Yesterday I tried to recover myself as fast as possible to prepare for my match today, and I’m still very nervous because I really want to win the matches for my country. This tournament is very emotional for me, but I’m very happy with the win today."
She added: "To be honest, I’m very happy that I’m here, that I’m in a safe place with my sister, and I’m happy to do the thing that I love, playing tennis. Every point that I’m playing here, I’m enjoying a lot, and especially with the situation that we have now, I’m enjoying it like a thousand times more. I’m going to try my best to win my next match."

'The hardest match in my life emotionally' - Ukraine's Yastremska on tennis during invasion

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