The Canadian butterfly specialist won gold in the women's 200-metre final at the Commonwealth Games to complete a remarkable comeback after being diagnosed with a career-threatening anxiety disorder in 2011.
Lacroix was having a difficult time in the leadup to the London Olympics and found herself constantly on edge as the pressure to make the team mounted following a string of poor results.
The Pont-Rouge, Que., native eventually sought help, and it started her on a path to the top of the podium at the Tollcross International Swimming Centre.
"When I was diagnosed with anxiety, I wasn't sure if I could ever go in the (starting) blocks again," said the 30-year-old Lacroix. "I took it step by step. I did one race and then I made the Olympic team.
"Now to be able to race some of the fastest girls in the world and win is just so incredible. I know how hard it was to get back to this level so now I appreciate it even more."
Lacroix said she seriously contemplated quitting the sport in her darkest moments, but decided to continue after lengthy discussions with coaches, officials and team doctors.
"The main goal was for me to be healthy and swimming at that level, it's not for everybody, and you need to be healthy to do it," said the two-time Olympian. "Everybody was fine with whichever decision I took."
Lacroix touched the wall first in a time of two minutes 7.61 seconds on Monday, but initially wasn't sure if she had done enough to get her first gold at the Commonwealth Games.
"I was really confused. For some reason I couldn't see the board — I couldn't see my name or my time," she said. "I turned and I saw that there was one light on my block, so that my meant I won. I also had the TV camera in my face so that was a pretty good cue."
Aimee Willmott of England was second in 2:08.07, while Australia's Maddie Groves captured bronze in 2:08.44.
Katerine Savard — who won the 100-metre butterfly earlier in the competition — led for the first 100 metres, but the Pont-Rouge native faded late and finished eight.
Lacroix won bronze in the 100-metre butterfly at the 2006 Commonwealth Games and took home a silver in the 200-metre event four years ago. She was fifth halfway through Monday's race and third with 50 metres to go before kicking things into another gear to bring home Canada's third gold medal in the pool.
"I expected a tight race and it was," said Lacroix. "It's just an amazing feeling. I really wanted gold. I already have bronze and a silver in the Commonwealth Games so it's a very special thing to get the gold tonight."
Lacroix's victory was Canada's second podium finish of the night after Brittany MacLean won bronze in the women's 800-metre freestyle.
The 20-year-old from Toronto smashed the Canadian record in the event with a time of 8:20.91 for her second medal at the Games following a silver in the 4x200-metre freestyle relay.
"I was just really looking towards to getting a medal," said MacLean, who lowered her own national mark by exactly four seconds. "I had so much fun getting the silver the other night with the relay team, but I really wanted to do one individually.
"I knew I was capable of a really good swim. I've been working hard all year. I just wanted to put it together when it mattered."
Jazz Carlin of Wales won the gold in 8:18.11 to set a Commonwealth Games record, while New Zealand's Lauren Boyle was second in 8:20.59.
MacLean, who finished fifth in Thursday's 200-metre freestyle and will race in the 400-metre freestyle on Tuesday, said chopping the Canadian record by such a wide margin didn't come as a complete shock.
"I wouldn't have told you that I was necessarily going to go that fast but knew that it was possible," she said. "You have to believe in yourself just as strongly as you believe in your training and believe in everything you've done. I went in here with the mindset that I was capable of racing those girls and I think I put up a good fight. I'll take bronze, definitely."
Swimming is a young person's sport as many of the competitors in Glasgow have shown, but Lacroix seems to be getting better with age now that she's healthy.
"I cannot control what the other girls are doing," she said. "All I can do is control me and I think I can be faster than when I was younger. I think I gave those girls a pretty good race tonight."
Notes: Prince William and his wife, the Duchess of Cambridge, were in attendance along with William's brother Harry, but the trio left partway through the event. ... In other finals involving Canadians, Calgary's Russell Wood finished seventh in the men's 200-metre backstroke; Tera van Beilen of Oakville, Ont., finished sixth in the women's 100-metre breaststroke, one spot ahead of Kierra Smith of Kelowna, B.C.; Edmonton's Richard Funk finished eighth in the men's 50-metre breaststroke; Victoria Poon and Sandrine Mainville tied for sixth in the women's 100-metre freestyle, while fellow Montrealer Alyson Ackman wound up eighth. ... Meanwhile, Ryan Cochrane will look to complete his double-gold repeat on Tuesday. The Victoria native — who already won the men's 400-metre freestyle here — qualified first for the 1,500-metre freestyle final. ... Calgary's Brooklynn Snodgrass qualified for Tuesday's final of the women's 50-metre backstroke.