Defending champion Serena Williams survived a hard-fought first-round encounter with Aravane Rezai to advance 6-3 3-6 6-1 at Wimbledon.
Williams broke down in tears after securing only her second victory since last year's SW19 title win following a near 12-month lay-off.
"To come back at Wimbledon and win is just awesome," she told BBC Sport.
Williams has not lost in the first round of her previous 44 Grand Slams, but was pushed hard in a 96-minute win.
Rezai, ranked 61st in the world, took the second set after going toe-to-toe with Williams's powerful groundstrokes.
But the Frenchwoman's momentum seeped away over the course of the decider, and Williams swept to an emotional win.
"It has been a disaster year but I have been praying, I have my family and I love tennis," said a tearful Williams after the match.
"This was probably the most emotional I've gotten after a match, after a win. For me it wasn't about winning the match, it was about being out there.
"I finally was in a position that I could have given up, I couldn't have come here, I could have sat home and said I've had a fabulous career and I don't have to work extra hard now.
"But it just really goes to show if you don't give up, you still have a chance."
She next faces Simona Halep after the Romanian beat Bojana Jovanovski in straight sets.
Williams spent nearly a year out of the sport with a foot injury and had emergency treatment for a pulmonary embolism in late February before her recent return at Eastbourne.
But it was a more commonplace complaint - an eye irritation - that troubled the American, whose serve was broken in a see-sawing first game.
Rezai, who led by a set and 5-2 in the pair's only previous meeting before slipping to defeat, played her part in establishing a surprise early lead with some energetic hitting from the baseline and a fortunate and decisive drop shot, but never looked secure in her brief time out in front.
As her serve cranked into gear, Williams held at her second attempt and broke back to level in the fourth.
After surrending her serve again in the sixth, Rezai was limited to occasional crowd-pleasing ripostes in the face of Williams's onslaught.
The 24-year-old checked Williams's momentum when she held her serve after losing the previous five games, but could only briefly stall Williams with a winning return on the first of three set points.
Galvinised by the start of the new set, Rezai rediscovered a length of shot and power that had troubled Williams early on in the match.
Her scurrying and hustling built the pressure on Williams, and the world number 25 cracked. Her previously impregnable serve faltered and she surrendered the sixth game with a double fault.
This time, Rezai retained her composure, her serve and the second-set lead and moved level.
But the European has endured a difficult start to 2011, securing only five wins in 12 tournaments since her father was suspended from all WTA events following an incident at the Australian Open, and was unable to maintain her form as Williams came through the stronger in the final set.
After ominously holding her serve to love to move 2-1 up, she made the breakthrough in the next game before an emphatic break to love in the sixth sealed a fading Rezai's fate.