And then she kicked herself for perhaps one of her biggest blunders of a heartbreaking two days of competition — keeping her daughter Anika away from the stadium Saturday night.
The 30-year-old from London, Ont., was a threat for a medal in the heptathlon at the London Olympics, but a disastrous high jump left her battling from too far behind. She finished seventh, missing out on the medal she'd had in her sights since she was fifth four years ago in Beijing.
She broke down and sobbed afterward, and the person she needed the most wasn't there. Zelinka had instructed her husband Nathaniel Miller not to bring their three-year-old daughter to Olympic Stadium, knowing it would be jam-packed, the event would run late, and it would take them a couple of hours to get home afterward.
"But I could really use a hug from her right now, it would just be the best thing ever," Zelinka said, wiping away tears. "She could have stayed up late. What was I thinking?"
Zelinka finished with 6,480 points, capping her performance with a gutsy run in the 800 metres — finishing second in two minutes 9.15 seconds.
British star Jessica Ennis won the gold with a score of 6,955 points.
Brianne Theisen of Humboldt, Sask., finished 11th with 6,383 points.
Zelinka, coming off a Canadian-record performance last month in Calgary, recorded personal bests in the hurdles, 200 metres and javelin. But her high jump early on Day 1 left her well back in 19th place, and then a so-so long jump on Saturday put her out of medal contention entirely.
"I don't know what to make of it because five of the seven was exactly what I wanted to do," Zelinka said, finally gathering herself after erupting in sobs. "Five out of seven isn't bad, but in heptathlon the jumps are not forgiving. I could have messed up a throw, or anything else, but the jumps are not forgiving."
Zelinka's 200 to end Day 1 catapulted her up into third place. It gave her hope.
"I got a second chance after Day 1 and I messed it up again with the long jump," she said. "That was over after that, you can't regain that, you can't regain that by beating people by two metres in the shot put, or racing 10 seconds faster in the 800, you just can't make up those points.
"I don't know . . . I don't know how or why or what. I don't know why I just could put even a half-decent jump together for either of them."
Zelinka was one of Canada's top hopes for a medal on the track in London, coming a day after Dylan Armstrong finished fifth in the shot put. Her Canadian-record score of 6,599 — or as her coach Les Gramantik joked $65.99 — was the third best in the world.
"I feel very much for her," said her longtime coach. "I will have other opportunities because I'm going to continue coaching so it's not going to end for me, but the bottom line is it will be difficult for her.
"She knows this could have happened. I know she knows. She cries because it's a missed opportunity."
Zelinka went into the 800 metres 198 points shy of third-place Lyudmyla Yosypenko of Ukraine, but the Canadian knew she had no hope of a medal.
Still, as the flashes of thousands of cameras followed the well-muscled runners around the track amid a deafening roar of support for Ennis, Zelinka sprinted from fourth place into second down the homestretch.
"Oh my god," she said. "I ran hard, hard knowing I wasn't going to get a medal regardless. I just wanted to run hard."
Zelinka, who sold her race bib from the Olympic trials on Twitter to raise money for her family to travel to London, was taken aback when asked about the possibility of hanging in until the 2016 Rio Games.
"Rio? What?" Zelinka said. "I was thinking Anika, I would love to be in the stands watching her compete, that would be the life, being in the stands and being all nervous for her, what Olympics will she be in? Rio, I don't know. Probably not. Our family cannot sustain this lifestyle, it's pretty crazy."
Zelinka and Theisen were originally ranked one place higher, but Germany's Lilli Schwarzkopf, originally disqualified from the 800, was reinstated to claim silver.
Cam Levin of Black Creek, B.C., raced to 11th place in a thrilling men's 10,000 metres, holding his own against a field that included some of the biggest names in the sport.
Mo Farah of Great Britain pulled away on the bell lap to win in 27:30.42. Levins, who ran the first 10,000 metres of his career only a couple of months ago, hung onto the lead group of 12 runners until the last 400 metres, finishing 11th in 27:40.68. Mohammed Ahmed of St. Catharines, Ont., was 18th.
"They ran the legs right off me, I wasn't able to kick at all," Levins said. "I'm really happy though, oh my gosh, at least shows me that I have the strength to run with these guys. I can't sprint with them yet, but that will come."
Levins will also race in the 5,000, which begins Wednesday.
The 23-year-old Levins has had a remarkable season, capping his NCAA career recently by winning both the 5,000 and 10,000 metres.
Saturday, he said, was a night he'd dreamed of his entire life.
"I've looked up to these guys for years, just waiting for the day I could run with them and experience that, and hopefully in the future I can run with them the whole time," he said.
The field included some of the biggest stars in distance running, with the likes Farah and Ethiopia's Kenenisa Bekele. Levins wasn't afraid of them.
"It's pretty cool but it's one of those things, you can't get overwhelmed by it," he said. "I feel like I'm going to be racing these guys for years to come, so you can't put them on a pedestal you just have to go out there and compete against them."
Away from the buzz of Olympic Stadium, Inaki Gomez recorded a Canadian record in the 20-kilometre race walk, held on a course in central London.
Gomez, from Burnaby, B.C., recorded a time of 1:20.58 to finish 13th, lowering the previous mark of 1:21.03 set by Arturo Huerta in 2000.
Gomez, a 24-year-old who moved from Mexico with his family when he was 11, was a competitive swimmer with his eyes on making the Olympics in that sport. He had to give up swimming in high school when he suffered damage to a disc in his neck in a car accident.
Ding Chen of China won the gold in 1:18.46 on the race-walk course that wound up and down a two-kilometre loop that began at The Mall and followed a course around Constitution Hill passing the spectacular backdrop of Buckingham Palace and the Queen Victoria Memorial.
But track and field at Olympic Stadium is proving to be the hot ticket in London, with full crowds of 80,000 pouring into the stadium for both the morning qualification and evening finals sessions.
Prince William and Kate Middleton, the Dutchess of Cambridge, attended Saturday's night session. Loud music blared over the loudspeakers. Before each event, video montages set to music of previous Olympic champions played on the big screen.
"I knew there was going to be lots of people but I couldn't hear myself think half the time, when I was in a heat with Jessica Ennis or any other British girl because they were just so loud," Theisen said. "it's vibrating, it's insane.
"The only way I can describe it is when you play X-Box Kinect and you do the track and field game and you can throw your hands up and the scream — that's exactly it, but 100 times louder."
Justyn Warner of Markham, Ont., advanced to the semifinals of the 100 metres in front of a jam-packed crowd of 80,000.
Warner was the ninth-place finisher running a personal best time of 10.09.
"The track was fast, blazing fast," Warner said. "I have to have the race of my life to get into the final and that's my plan. My goal this season was to go sub-10.10, and now the goal is sub-10.00."
Americans Ryan Bailey and Justin Gatlin were the two fastest qualifiers, in 9.88 and 9.97 respectively. Yohan Blake of Jamaica was third in 10.00 while Jamaican teammate and world record-holder Usain Bolt was ninth in 10.09.
Jenna Martin of Bridgewater, N.S., didn't advance out of the 400-metre semifinals, running 52.53 to finish seventh in her heat. Daundre Barnaby of Brampton, Ont., was sixth in his 400-metre heat in 46.04 and didn't move on to the semis.
Melanie Blouin of Quebec City cleared 4.25 metres in the women's pole vault, but it wasn't good enough to get her through to the final.