The teenage midfielder has been impressive early in to his Spurs career, and his driving runs from midfield have caught the eye of fans, pundits and seemingly other managers.
After signing for Spurs from MK Dons in January, Alli returned to the Dons for the rest of last season, helping Karl Robinson's men achieve promotion to the Championship - meaning his time at Spurs had to wait.
Now in the fold at White Hart Lane, Alli appears to Mauricio Pochettino's latest wonderkid, following on from recent success stories Nabil Bentaleb and Harry Kane.
However, it could have all been so different. As the Daily Mail reported back in January, Newcastle had agreed a deal to sign Alli, whilst Aston Villa also swooped in with a late offer to snatch the teenager.
In the end, they both missed out as Alli chose Tottenham over Newcastle and Villa - so how much will both clubs rue missing out on Alli's services?
Villa spent heavily on midfielders Idrissa Gueye and Jordan Veretout this summer, but at the time of their bid for Alli, it was Paul Lambert in charge at Villa Park, not Tim Sherwood - and the Scot's struggles may have played in to Alli's decision to choose North London over Birmingham.
Along with Jack Grealish and Adama Traore, Alli could have given Villa a solid base of young talent to work with over the coming years, and given their desire for an impact in the final third, Alli's driving runs into the box could have been a real asset for Villa.
Meanwhile, Newcastle saw Jack Colback thrive last year, but Cheick Tiote has become the forgotten man at St. James' Park, whilst Vurnon Anita hasn't lived up to his billing since arriving from Ajax in 2012.
The Magpies are attempting to bring in more young, English players - Karl Darlow, Jamaal Lascelles and ivan Toney have all arrived on Tyneside recently - and Alli would have been perfect, giving the club a young, promising midfielder to get fans excited for the first time in a while.
As it is, Tottenham are the ones who get to look forward to years of Alli's development and excellent performances, and it's fair to say that Villa and Newcastle may be wondering what might have been had they not left their bids for Alli so late in to the January transfer window; and now they must watch on and even face him as he becomes a Premier League regular.