The Magpies snapped up Sissoko for a nominal fee last month after the France international had been frozen out by his former club Toulouse following his failure to sign a contract extension.
The 23-year-old made an instant impact, impressing against Aston Villa before scoring a vital brace to snatch a win for the North-East side against European champions Chelsea last weekend.
Tottenham, along with a host of other top European clubs such as Juventus and Inter Milan, were thought to be interested in signing Sissoko, but the considerable Gallic contingent in the St James' Park dressing room convinced the dynamic midfielder to move to Tyneside on a six-and-a-half-year contract.
Villas-Boas is a big fan of Sissoko, and Newcastle's other January signings like Mathieu Debuchy and Yoan Gouffran, so he knows his team will have to be on their guard when the Tynesiders arrive at White Hart Lane.
"Most of their signings have gone straight in and have had the right impact," the Spurs boss said.
"Sissoko was a great grab. A couple of years ago he was being linked with the top clubs in the world and to get him at such a low price was a massive coup for them."
While Toon boss Pardew splashed the cash to acquire some five new French additions to his squad, Villas-Boas was rather less active in the transfer window.
Lewis Holtby was the only senior signing the Portuguese made as efforts to bring in Internacional striker Leandro Damiao failed.
The Spurs manager is content with his squad, however, and is extremely pleased with how Holtby has settled in following his move from Schalke.
The Germany international has impressed off the bench in his two appearances so far, and he could start out wide on the left if Villas-Boas decides to go through with his plan to play Gareth Bale behind either Emmanuel Adebayor or Clint Dempsey.
"He's made an immediate impact in the team in both games," the former Chelsea manager said of the £1.25million midfielder.
"Lewis offers further options playing from the channels coming in.
"We haven't seen him in this position yet, but he finds comfort in that position because he played it before for Mainz.
"At the moment he's playing fantastically well. Hopefully we will continue to see him progress."