The British and Irish Lions suffered a first loss on tour when they went down 17-13 to South Africa A in a full-blooded contest at Cape Town Stadium on Wednesday.
Trailing by 14 points at half-time, the tourists scored 10 unanswered points in the second half, but a Zander Fagerson knock-on in the final minute cost them a chance to snatch victory.
A Springbok-packed South Africa A side won despite being temporarily reduced to 13 men just before half-time when scrum-half Faf de Klerk and flanker Marco van Staden were sin-binned.
Before the kick-off, Lions captain and scrum-half Conor Murray called the fourth match of the Lions tour a "fourth Test" given the strength of the South Africa squad.
His assessment was spot on as the Lions, who had earlier scored 27 tries in three runaway victories over weak franchise sides, suddenly came up against strong opposition.
Murray said: "It was a different level today. We learnt a lot of things. We can be proud of ourselves, especially in the second half.
"It was really, really physical and it's something we are going to benefit from. We have not come up against that level of physicality on the tour.
"We know the Boks are going to be really physical. The breakdowns are going to be a massive deciding factor in the Test series.
- 'Proud of ourselves' -
South Africa A captain and centre Lukhanyo Am said: "We can be very proud of ourselves. It was a good outing. We did a lot of good stuff and there was also stuff that did not go our way.
"We will be able to judge and analyse where we need to improve in the days ahead. We are really excited to be back in the midst of things and we will go back to the drawing board to see where we can improve."
The Lions should have little difficulty overcoming another franchise, the Stormers, in Cape Town on Saturday, but then comes a three-Test series against world champions South Africa from July 24.
It was a mixed day for the visitors as they earlier received a boost with news that original tour captain and lock Alun Wyn Jones had been passed fit to join the tour.
Jones suffered a shoulder injury in a warm-up against Japan on June 26 and withdrew from the tour only to make a remarkable recovery and is expected to arrive in Cape Town on Thursday.
Ronan Kelleher flew with Wyn Jones, swelling the number of hookers available to coach Warren Gatland to four for the remaining four matches.
All the South Africa A points came within 34 minutes as fly-half Morne Steyn, who turned 37 last Sunday, kicked a penalty and converted tries by wing Sibusiso Nkosi and Am.
A concern for the hosts will be an early second half head injury to star flanker and reigning World Rugby Player of the Year Pieter-Steph du Toit. He was replaced by Rynhardt Elstadt.
Fly-half Owen Farrell, a last-minute replacement after Dan Biggar suffered a minor ankle sprain, slotted two penalties and added the extra points to a try from prop Wyn Jones.