Ziyech’s snappy through ball was controlled brilliantly by Donny van de Beek, who took his time before placing the ball into the corner past Hugo Lloris.
Spurs spent the rest of the game chasing but couldn’t find the all-important equaliser as Ajax held on to a lead they can take back to the second leg in Amsterdam.
After the game Gullit, who played for Ajax’s rivals PSV and Feyenoord, believes Mauricio Pochettino’s players let themselves down.
“For me, a lot of Tottenham players were disappointing,” he told beIN Sports.
Dele Alli could not stamp his authority on the game (Image: GETTY )
“I see them every week in the Premier League but Dele Alli, oh my God, technically he was so bad.
“Victor Wanyama, technical-wise [was bad], Danny Rose also.
“I see them every week and I think how is it possible to make so many mistakes.
“I know they’re under pressure but you need to know what to do with that pressure and they didn’t.”
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Donny van de Beek scored the only goal of the game as Ajax ran out 1-0 winners (Image: GETTY )
Ajax are looking to win their fifth European cup while Spurs are trying to reach their first ever Champions League final.
Spurs will be boosted by the return of Heung-min Son, who will come back from suspension in the return leg.
Harry Kane will remain sidelined, however, but there is hope that the striker can make the final, should Tottenham overturn their deficit.
The other semi-final first leg will be played on Wednesday by Liverpool and Barcelona at the Nou Camp.