Venus Williams soared to her first victory over a top 50 opponent in four years as she defeated Camila Giorgi at the WTA event in Birmingham on Monday.
Ignoring a knee problem that needed treatment in the first set and left her close to tears, Williams won a singles match for the second time in nearly two years.
The 43-year-old battled to a 7-6 (7/5), 4-6, 7-6 (8/6) first-round win over world number 48 Giorgi in three hours and 16 minutes.
Williams had played a grass-court event in the Netherlands last week for her first tournament appearance since January, and she was understandably rusty at times against Giorgi.
But the five-time Wimbledon champion also hit her stride in spells during an enthralling encounter.
She converted her second match point in the final set tie-break, holding her arms aloft and repeatedly pumping her fist as the crowd roared in delight.
Williams might be well into the twilight of her glittering career, but the seven-time Grand Slam champion still relishes the feeling of winning a hard-fought match.
"This one is especially sweet because I have been away from the tour for so long," she said.
"The last couple of years, I've had little to no matches and that's very challenging.
"I almost feel like when I'm on the court, I'm reminded of things I used to do that worked really well, so there's a lot of memories and deja vu."
Williams faces a last-16 tie against the Czech Republic's Linda Noskova or Latvian second seed Jelena Ostapenko.
"Tennis is awesome. There are so many people that would love to do what I'm doing right now, so I don't take it for granted," Williams said.
"I faced some huge challenges in the match. I think that brought the emotion out."
There were different emotions for another former top-10 player returning to grass, with Elina Svitolina beaten 6-2, 6-0 by Czech 18-year-old Linda Fruhvirtova in less than an hour.
Svitolina made a brilliant comeback on clay following the birth of daughter Skai last October, reaching the quarter-finals of the French Open, but the 28-year-old could not find her feet on the grass.
"I was struggling at the beginning, and, on the grass, you have no time to adjust. For me, it didn't happen today, but I'll go on the practice court and try to do better next time," she said.