Starting for the first time in the tournament, the 19-year-old City striker was clearly keen to impress Ian Foster ahead of next week's semi-final.
Having already qualified for the final four before tonight, England made seven changes to the side that thrashed Serbia on Wednesday.
That rotation included City defender Callum Doyle, who began on the bench after starting each of the first two games.
The 18-year-old did come on for the second half, replacing Peterborough's Ronnie Edwards on the left of a back three.
On a sodden pitch in Žiar nad Hronom, Delap's goal that proved to be the winner came after just six minutes.
Played through by Tottenham's Alfie Devine, he raced on to the ball ahead of the Israel defenders and unleashed a typically emphatic left-footed hammer blow into the roof of the net.
An early goal for England! ⚽️— Match of the Day (@BBCMOTD) June 25, 2022
Liam Delap collects a Alfie Devine pass to fire past the Israel goalkeeper and put the Young Lions in the lead.
Israel U19 0-1 England U19
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He remained a thorn in Israel's side throughout the first half and had England's other outstanding chance before the break - playing a neat one-two on the edge of the box before firing a shot narrowly wide.
Delap was the most likely early in the second half too, sending a left-footed volley wide before a neat turn of his own created room for a shot that was blocked in front of goalkeeper Tomer Tzarfati.
The saturated pitch played more of a role as the match wore on, slowing England's passing and tiring the players quicker than may otherwise have been expected.
With England keeping their opponents at arm's length, Delap's night came to an end with just short of 15 minutes remaining.
There was still time for one more England chance however, and it fell to the feet of Doyle.
Venturing forward during a move down the left, he found himself in the centre of the box when a low cross came in. Our defender turned it goalwards, only to see Tzarfati tip it wide.
Having won all three matches and topped Group B, England will now face Group A runners-up Italy at the semi-final stage on Tuesday.
The other semi-final will be played out between Israel and France before the final next Friday. The locations and kick-off times of the semi-finals will be confirmed by UEFA on Sunday.
By reaching the semi-final, England have also qualified for next year's Under-20 World Cup in Indonesia.