Alli, 19, looked set to sign for Newcastle back in January having starred in League One with MK Dons. As reported by the Daily Mail, the deal was agreed and Alli appeared to be heaving to the North East - only for Tottenham to swoop in at the last minute and take him to White Hart Lane.
Whether it was Newcastle dallying for too long that allowed Tottenham to steal Alli or Spurs simply outbid them, Newcastle can't afford to see top English youngsters join their rivals, and action needs to be taken in January.
With Alli thriving in the Tottenham midfield, and earning call-ups to the England senior squad, Newcastle should be looking to bring a young, English midfielder of their own in January - and Leeds United's Lewis Cook stands out as a prime target for the Magpies.
Recent reports from The Chronicle have suggested that Newcastle are keen on a January move for Cook, but rather than waiting until the end of the window as they did for Alli, now is the time for Newcastle to step in early and try to prise the 18-year-old away from Elland Road.
Cook has shown great ability since coming in to the Leeds side at the start of last season, with his tenacity in the middle of park impressing many - much as Alli's did with MK Dons.
With energy in the middle of the park, Cook could bring real drive to the Newcastle midfield, and it's time for Newcastle to make a statement by targeting one of England's finest up-and-coming talents, rather than solely shopping abroad for first-team additions, as they did over the summer.
There is plenty of interest in Cook's signature; the Daily Star reported earlier this week that Bournemouth and Stoke have joined Liverpool and Manchester United in targeting Cook, so the Magpies can't afford to wait around this time, and should be making Cook one of their top priorities in the January transfer window.
They may have missed out on Alli almost a year ago, but if they learn their lesson and find their own talented, young English midfielder, they can still make a huge stride forward this season.