The 26-year-old, who started the race from 10th on the Silverstone grid, saw his hopes and aspirations deflate just four corners into the race.
As he accelerated through the fast right-hander and positioned his Mercedes-powered Sahara Force India for the next left-hander, his car suddenly speared off the circuit.
In the split second he had inched his car to the right of the track for the left-hander, his right-rear tyre had been clipped by the front left wing of Romain Grosjean’s Lotus.
“I knew immediately there was no pressure in the tyre and it had come off the rim,” a deeply disappointed Di Resta admitted.
“That meant I had to nurse the car back very slowly to the pits, and believe me it was a long way.
“Silverstone’s 3.6-miles long, and we’d only completed four corners: but all I could do was try to be as careful as I could be.
“Unfortunately there was also quite a bit of damage to the floor, and on F1 car’s that spells trouble.
“There was definitely no way I could continue. That was it: game over.”
And the Scot, who was eager to score world championship points in front of his growing army of supporters, admitted the end of the race had come as a blow to him.
“You have no idea how disappointing it was to go out just a few seconds after the start of the race,” he said.
“For me the British Grand Prix at Silverstone is the biggest race of the year, and I believe we had a car capable of doing something special on the day.
“We’d compromised our qualifying performance in the torrential wet conditions on Saturday because we’d gambled on the race being dry and had set the car up accordingly.
“So you can imagine how I, and the rest of the Sahara Force India crew felt when we saw the blue skies and sunshine on Sunday.
“We knew we had the right setup and could make an impact, especially starting from 10th on the grid. But we never got the opportunity to show our true pace.
“What made it even more difficult was I knew there were so many people out there supporting me who had really battled through the conditions and braved the elements.
“I had a lot of family and friends at the track, plus we had a the guys from the team’s HQ, which is just across the road from Silverstone, at the track. And I know there were loads of Saltires flying around the circuit.”
At the head of the field, Alonso, who had started the 52-lap race from pole position, led until lap 48 before Webber pounced.
The Spaniard, who at one stage had led Webber by more than six seconds, began to struggle over the closing laps as his Pirelli tyres lost grip.
And in the end he was defenceless against the incessant pressure which was applied by Webber.
It was Webber’s ninth grand prix win of his career and moved him to within 13 points of world championship leader Alonso in the title race.
Behind the podium finishers, Alonso’s Ferrari team-mate Felipe Massa was forth, just ahead of the two Lotus cars of Kimi Raikkonen and Grosjean: the Frenchman’s finish merely rubbing salt into Di Resta’s wound.
Seven-times world champ Michael Schumacher was seventh, with the McLarens of Lewis Hamilton and Jenson Button sandwiching the Williams of Bruno Senna in ninth.