Harry Winks scored the hosts’ other goal with a freak 45-yard strike into the top corner, which was surely an over-hit pass for Vinicus or Gareth Bale.
Spurs finished a feelgood night with four youngsters on the pitch, in Jack Clarke and debutants Alfie Whiteman, Harvey White and Dane Scarlett, and their attentions can now turn to Chelsea on Sunday.
After the 2-0 win over Manchester City last weekend, Mourinho made 10 changes, with only Tanguy Ndombele keeping his place.
The manager had threatened to stop rotating his squad in the Europa League after his fringe players failed to impress in an abject defeat to Antwerp last month but here they did exactly what was required of them.
It is difficult to know whether Vinicus will make as big an impact in the Premier League as he did in Portugal, where he finished top-scorer last season, but clearly he is good enough for this stage.
More important than his display, his presence allowed Mourinho to keep Kane and Son fresh for Sunday’s six-pointer at Stamford Bridge.
Despite two days’ less rest, Spurs may well be fresher than the Blues after Frank Lampard used a smattering of first-team players in Tuesday’s visit to French side Rennes. Spurs are reaping the benefits of having a strong squad.
Vinicius’ first goal for the club was a well-taken finish, which should boost his confidence after a mixed start which saw him hooked at half-time of the defeat in Belgium, along with three teammates.
He added a second before half-time after unselfish play from Dele, who squared after Ndombele’s shot was well-saved by Ludogorets goalkeeper Plamen Iliev.
Spurs’ intensity dropped after the interval but Winks put the contest to bed with a spectacular long-range strike, which was surely intended as a pass. The England midfielder’s amused reaction certainly suggested it was a mistake and he confirmed as much in his post-match interview.
Vincius, who impressed with his hold-up play again, then set-up Lucas after more good work from Dele but 16-year-old Scarlett nearly grabbed the headlines by going close late on.
It was difficult to glean much from the game, given the lack of threat posed by a depleted Ludogorets, but if nothing else it may prove significant for Dele.
The 23-year-old has been hooked at half-time of two of his three previous starts this season – and by the hour on the third – and has not played since being one of four players replaced at the interval of the 1-0 defeat to Royal Antwerp last month.
Clearly, he needed to impress here – and quickly.
Dele’s first assist was a slice of luck as his pass, intended for an offside Bale, ricocheted off a defender into the path of Vinicius, who finished coolly.
There was nothing lucky and plenty to admire about Dele’s second assist. Ndombele’s low shot forced a fine one-handed save from Iliev and Dele pounced on the loose ball, unselfishly squaring for Vincius to finish again.
Mourinho must have been satisfied, for Dele survived the interval and lasted until the 81st-minute when he was replaced by White.
A truer test of Mourinho’s feelings will be the matchday squad for Chelsea. Dele loves playing the Blues and a place on the bench would signal a thawing of Mourinho’s feelings.
A routine evening was made noteworthy by a late triple substitution by Mourinho, including the introduction of Spurs’ youngest ever player in 16-year-old Scarlett, a promising forward who has been scoring for fun in the U18s.
Goalkeeper Whiteman and midfielder White also played the final ten minutes in a feelgood move from Mourinho, who has often been accused of ignoring young players.
Scarlett twice went close in the final ten minutes, by which point a depleted Ludogorets had fully checked out, and White also rasped an effort just wide.
Blooding young players and giving supporters something to talk about is an encouraging approach at this stage of the competition and long may it continue.
Terms: Min £10 Same Game Multi bet on any EPL match this Fri – Sun. Free bet valid for 72 hours, awarded at bet settlement. Excludes cashed out bets. T&Cs apply.
We may earn commission from some of the links in this article, but we never allow this to influence our content. This revenue helps to fund journalism across The Evening Standard.