This appeared a golden chance for Konta to become the first British woman to win a slam singles crown since Virginia Wade at Wimbledon in 1977, but she let winning positions in both sets slip away to lose 7-5 7-6 (2).
In the end it was 19-year-old Vondrousova who showed the greater composure, coming back from 5-3 down in both sets to set up a final clash with Ashleigh Barty, who defeated 17-year-old American Amanda Anisimova 6-7 (4) 6-3 6-3.
The match had originally been scheduled for Thursday but a wash-out of Wednesday’s quarter-finals and more rain forecast for Friday gave organisers a major headache.
Their solution was to play the two women’s semi-finals at 11am away from the main Philippe Chatrier court, which hosted the men’s last-four matches as scheduled.
Konta and Vondrousova were sent out to Roland Garros’s third stadium, the new 5,000-capacity Simonne Mathieu, but it was never more than a third full throughout the match.
Konta said she was surprised when she saw the schedule and, asked if she felt like she was playing in a slam semi-final, the 26th seed added: “In terms of the surrounding and the occasion, probably not.”
Steve Simon, the CEO and chairman of the WTA, put out a statement on Thursday describing the schedule as “unfair and inappropriate”, while former world number one Amelie Mauresmo branded it a disgrace.
“I think more than anything, what is tiring and what is really unfortunate is that female athletes have to sit in different positions and have to justify their scheduling or their involvement in an event or their salary or their opportunities,” added Konta.
“And to give time to that is even more of a sad situation than what we found ourselves in today in terms of the scheduling.
“I don’t want to sit here and justify where I’m scheduled. That’s not my job. My job is to come here and entertain people.
“I feel I gave people who paid for tickets every chance to enjoy their French Open experience and if the organisers do not feel that is something that can be promoted and celebrated, then it’s the organisers you need to have a conversation with, not me.”
On the court, Konta found herself in the unexpected situation of being the most experienced of the four semi-finalists.
This was her third time in the last four at a major after losses at the Australian Open in 2016 and Wimbledon two years ago, and, although she did not admit as much, this one will surely sting more.
It was Vondrousova who made a nervous start, with Konta winning the first 10 points. She missed a glorious chance to win the 11th, too, and that began to feel more and more important as the match wore on.
Voundrousova settled but Konta should still have won the first set. She had three set points at 5-3, missing a wild drive volley on the first, only for her opponent to reel off four games in a row.
The second set was virtually a repeat, with Konta again serving for it at 5-3 and double-faulting on break point. She at least forced a tie-break this time but it was Vondrousova who played the smarter throughout.
Konta has been so composed and assured this tournament but here the old nerves bubbled to the surface and her tactical thinking was muddled.
The 28-year-old, though, insisted she had no regrets.
“I wouldn’t say I had a good tournament, I had a great tournament,” said Konta, who will climb to 18th in the rankings. “There is nothing for me to be disappointed in or upset about. I lost a tennis match, but I also won five.”
In the men’s draw, it was deja vu for Roger Federer as his return to Roland Garros ended in another clay-court defeat to Rafael Nadal, the Spaniard handling the windy conditions better to claim a 6-3 6-4 6-2 victory and reach a 12th final.
Novak Djokovic and Dominic Thiem will have to come back at around Saturday lunchtime to complete their match after rain forced an early end to play.
After Thiem won the opening set, Djokovic hit back to level but had just gone a break down in the third to trail 6-2 3-6 3-1 when the rain returned.