The 30-year-old netted the opener for Spurs as they overcame Anzhi Makhachkala 2-0 on Thursday, leaving himself just one shy from Martin Chivers's milestone of 22 in continental competition.
"It was another great goal, a great finish," Villas-Boas told reporters. "It's really good to see him out there again doing extremely well whenever he's given the opportunity.
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"I think he has the ambition this season to go even further up the ladder in this record tally behind Martin Chivers and as an all-time goalscorer so I think that plays highly in his motivation, definitely."
The 35-year-old hinted, however, that he may again drop the striker – who has made all four of his starts this season in cup competitions – for Roberto Soldado when they visit his former employers, West Ham, in the Premier League on Sunday.
He continued: "We have to judge recovery and the fact that JD was involved [on Thursday] and Soldado wasn't.
"Everything will come into consideration. We have been extremely happy with the performances of both. It is a question of deciding what is best for the team."