It was a 0-1 loss on the south coast against Bournemouth.
19-year-old Dean Huijsen was able to nod in 1-0 on a corner in the 17th minute after sloppy defensive play from the guests.
Spurs had an equalizing ball in from Son Heung-Min, but he was offside when he scored the rebound after Kulusevski's shot in the 59th minute.
Bournemouth also had a goal disallowed for offside, also after a VAR review.
Tottenham, who were overtaken in the table by Bournemouth, are ninth and still have six points up to a Champions League spot.
Kulusevski played the entire match while Lucas Bergvall was substituted in in the 80th minute.
Fulham won over Brighton with 3-1 after two goals in the last ten minutes. The guests' Matt O'Riley scored an own goal in the 79th and Alex Iwobi set 3-1 in the 87th with his second goal in the match.
National team midfielder Yasin Ayari watched the entire match from Brighton's bench.
