21-year-old Marney replaced Wayne Routledge for the final third against Holland at Pride Park.
"It's fantastic for Dean and it's important for the club too. It just goes to show the progress he's made as an individual," said Spurs reserve team coach Clive Allen.
"Tom has terrific passing range. I think Spurs have signed a wonderful player. He can be a very good player either as a defender or a midfielder, but if he settles in one position, he can become great in one. I don't think Spurs have bought him as a squad player. I think they've bought him as someone who can go straight into the first team," said England Under-21 coach Peter Taylor.