Skipper of Chris Hughton's reserve side, Hillier has been bombing up and down the right flank in his wing-back role to great effect.
Another fine display against Wimbledon last week was capped with a goal in front of the watching George Graham.
Hillier has now been selected for a preliminary Welsh Under-21 squad for forthcoming European Championship matches in March.
Team-mates Simon Davies is also in the squad. Hillier said: "I've been selected for a preliminary squad of 24 that they will eventually drop down to 20. Hopefully I'll manage to stay in the squad.
"A couple of years ago I wouldn't have imagined playing for the Under-21s. I even thought I was too old but Chris (Hughton) gave me the letter and it was great news."
The 21-year-old from Neath now has his eyes on a greater prize - another contract at Spurs.
"Things have gone all right this season," he said. "My contract is up at the end of the season so hopefully I'll get a new one.
"It is hard to break through here but you have to believe and I suppose getting into this Welsh squad will only help my contract talks."
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Ian Hillier's outstanding form has earned a first team squad call this season and now an international chance - but there is one more target he is chasing.