Wales had two players sent off as they fell to a late Israel winner in their opening Uefa Under-21 qualifier.
Israel took a 26th-minute lead through Toto Tamuz, but Wales drew level on the hour through Wrexham's Marc Williams.
Idan Srur restored Israel's lead on 64 minutes only for Williams to hit back again a minute later.
A 78th-minute penalty from Lior Refaelov gave Israel the victory, as Williams and Craig Davies were sent off inside the final 10 minutes in Holland.
A Football Association of Wales official claimed the Wales players had been provoked by their opponents, saying: "We have had reports of people being spat at, and two players were dismissed after being struck."
The match was switched to the neutral venue in Waalwijk because of Israel's conflict with Hezbollah.
To stand any chance of qualifying for the next round, Wales must beat Turkey in their second and final game in the three-nation group at Ninian Park on Saturday, 2 September.
The 14 group winners from the qualifying round go forward to two-legged play-offs.
And the winners of those seven matches in October will then join host nation The Netherlands in next summer's finals.
Wales Under-21 manager Brian Flynn:
"Both dismissals were when the ball was out of play, they were for retaliation - and the lads have said they were punched.
"I didn't have a clear view of what happened, but we will look at both incidents when we have all the evidence and have seen the referee's report, before deciding whether we will appeal or take the situation further.
"But it's fair to say that retaliation gets you nowhere. When you play at this level you must have international level self discipline, you have to maintain those standards whatever happens to you.
"I would expect Turkey to be too good for Israel, but then we will have to beat them, and that will be tough.
"But we can produce a top-level performance when Turkey come to Ninian Park, and it could all go down to goal difference."
Wales Under-21: Lewis Price (Ipswich), Neal Eardley (Oldham), Joe Jacobson (Cardiff), Kyle Critchell (Southampton), Craig Morgan (MK Dons), Mike Williams (Wrexham), Darcy Blake (Cardiff), Andrew Crofts (capt, Gillingham), Craig Davies (Wolves), Dave Edwards (Shrewsbury), Arron Davies (Yeovil).
Subs: Chris Gunter (Cardiff), Adam Davies (Cambridge), Grant Basey (Charlton Ath), Lloyd James (Southampton), Matthew Collins (Fulham), Marc Williams (Wrexham), Wayne Hennessey (Wolves).