Giles, who must ready a new-look Twenty20 squad for two internationals against New Zealand at The Oval on Tuesday and on Thursday - a fit-again Kevin Pietersen will also be back for the second - could only watch as England blew a winning position against India at Edgbaston on Sunday.
Giles, however, does not believe there is a national mental block when it comes to clinching the ODI silverware. "I don't think it is a mental issue. It does happen," he said of England's latest setback. "We're going to be low for a while ... I won't sleep that easily ... but at the same time, we've made every effort to prepare and to plan to get it right."
England had four wickets down and needed just another 20 runs from 16 balls, with two set batsmen at the crease in pursuit of 129 for seven in a match shortened by rain to 20 overs per side.
But England lost fifth-wicket pair Eoin Morgan and Ravi Bopara to successive deliveries from Ishant Sharma and eventually fell five runs short, therefore extending their sequence of failure in ODI global tournaments to 17 spread over 38 years - including five defeats in finals.
Bopara, who had taken three for 20 with his medium-pace, and Morgan appeared to have a piece of history in their hands for England. But theirs were the first two of four wickets to fall for three runs, as it all suddenly went pear-shaped again.
"You could say 'just play the next 16 balls'. But you can't, you've still got to score," said Giles. "Rightly so, Ravi and 'Morgs' targeted that over. They thought we'd go a long way to winning the game if we targeted that over. It was the right thing to do tactically, and when you go for shots you run the risk of getting out."
England appeared to have done so much of the hard work, and Giles is not about to lose faith after one blip - albeit on the biggest stage. "I thought at halfway to score 130 to win the Champions Trophy in 20 overs, you'd take that.
"But then losing those wickets in a clump up front, I thought Bopara and Morgan played fantastically well to get us into a position where we needed 20 off 16. We were starting to think, maybe wrongly, that we're going to get there.
"But this game does have those twists and turns, and it was always going to be difficult with new guys going in and scoring quickly. Whether you've got the powerplay or not, to score quickly against those bowlers is hard. It is disappointing, but I can't fault the guys in this Champions Trophy."