Fernando Alonso has failed to qualify for the Indianapolis 500 after a humiliating return to the USA's biggest race for the McLaren team.
The two-time Formula 1 world champion was fourth fastest of six drivers vying for the final three places on the grid on what is known as 'Bump Day'.
Alonso's 227.353mph four-lap average was pipped by American Kyle Kaiser by just 0.019mph with the last run.
It is a bitter blow for Alonso, who left F1 to focus on winning Indy.
"A difficult week, no doubts," Alonso said on social media. "We tried our best, even today with a completely different set up and approach, four laps flat on the throttle but we were not fast enough.
"It's never easy to drive around here at 227mph+, and want more speed... We tried our best and we've been brave at times, but there were people doing better job than us.
"Success or disappointments only come if you accept big challenges. We accepted. Thanks to the massive support always here at the speedway and everyone at home."
Problems hit McLaren
McLaren said they were "hugely disappointed" not to qualify.
"It's been a tough week for the team. We're sorry that our fans didn't get the chance to cheer us on at the Brickyard," said the team.
The 37-year-old is making his second appearance at the historic 2.5-mile super speedway.
In 2017, he qualified fifth and led for 27 laps of the race before retiring with an engine failure in the closing laps, while driving a McLaren-branded car for the leading Andretti team.
For his second attempt, McLaren chose to set up their own team from scratch and there will be questions about a number of the decisions that were made along the way.
The project has struggled from the very beginning and a series of problems through practice last week left Alonso badly under-prepared for the the weekend's qualifying.
Alonso was 31st fastest on Saturday, which meant he just missed out on a guaranteed place on the grid afforded to the fastest 30 drivers.
Overnight, McLaren sought help from the Andretti and Penske teams - two of the three biggest in Indycar - as they sought to improve the difficult handling of their car.
It meant Alonso went into his single four-lap shot blind, and it was not to be.
What went wrong?
The questions as to how this happened will all be focused on McLaren, as Alonso has already proved he can be competitive at Indy.
Nevertheless, it has been a difficult experience for Alonso, who left F1 last year to concentrate on his ambition to win motorsport's unofficial 'triple crown', of Indy, Le Mans and the Monaco Grand Prix.
Alonso won Le Mans last year and has twice won Monaco. Some consider the F1 aspect of the triple crown to be the world title, but as the Spaniard has won both, it is academic in his case. Only Graham Hill has ever won all three races.
It was always going to be a big ask to set up a new team and be competitive at Indy, but few expected McLaren to have as many problems as they have.
Alonso lost the vast majority of the first day of Indy practice on Tuesday with an electrical issue, crashed on the second and did not run at all on the third, as McLaren struggled to build a new car, partly as a result of discovering an engine problem.
Alonso's only trouble-free day before qualifying was Friday, but McLaren effectively had to cram an entire week's preparation into that one day.
On top of their difficult week at Indy, there will be questions as to whether McLaren prepared adequately for their first Indy campaign as a self-run team since the 1970s, and inevitably there will be a major inquest as to what has gone wrong.
Run by former Force India F1 deputy team principal Bob Fernley, McLaren's Indy team scheduled only one test day before running started in preparation for the 500.
McLaren spent a day at Texas Speedway in the second week of April, on which problems restricted running, before the official first test day at Indy on 25 April.
For Alonso, there will be further questions.
Winning Indy is his last big ambition for his career. He will want to return to have another go at winning it, but after this year's experience, will he be prepared to risk another try with McLaren, or prefer to try to do a deal with one of the sport's big teams? If it is the latter, Penske will likely be his first focus.
Rest of the field
The other two drivers to make it on to the grid on 'bump day' were Canadian James Hinchcliffe and American Sage Karam.
British former F1 driver Max Chilton was slowest of all and did not qualify, while Mexican Patricio 'Pato' O'Ward, who recently joined Red Bull's F1 junior driver programme, also missed out.
The top nine places on the grid were also being resolved on Sunday as the fastest drivers in Saturday's session took part in a shoot-out for pole position.
Pole was taken by Frenchman Simon Pagenaud, his first at Indy, driving for the Penske team, ahead of Americans Ed Carpenter and Spencer Pigot.
The race, over 200 laps, is on Sunday 26 May at 1830 BST.