Despite going behind early to a Bruno Fernandes penalty, Spurs recovered to embarrass United 6-1 at Old Trafford.
The link-up play between Heung-min Son and Harry Kane was particularly impressive, as they displayed their excellent cohesion again this campaign.
Berbatov says his former club have been mightily impressive recently.
"I've been so impressed with Spurs of late, and we can't take anything away from them. I think even if United kept 11 men, Spurs would still have won easily, he told Betfair.
"The partnership between Kane and Son is only getting stronger, and the addition of Bale soon is frightening to think about. I was also impressed with [Tanguy] Ndombele and [Moussa] Sissoko in the middle of the pitch, and [Pierre-Emile] Hojbjerg from Southampton was also excellent. Overall for Spurs, it was a perfect performance.
Berbatov reckons that the addition of Bale will bring a winning mentality to Tottenham this season, and that the forward line with him included will be a frightening prospect for opposition defences.
"It's interesting that the run of form has come as they signed Bale, even though he hasn't played a minute!" he added.
"Hopefully, he isn't training properly in heavy sessions, but interactions around the club can have an impact on the squad, and bringing his winning mentality to these guys.
"If he can transfer that on to the pitch, that will honestly be just terrifying for all other clubs. We all saw the video of Bale with the win over Chelsea, and you can see how much he still cares and how passionate he is.
"At Madrid, for all he was training, he wasn't really part of the team, and he felt left out. He would not have felt part of the team, as he wasn't allowed to contribute anything. The opposite is when you are part of the team- even if injury is keeping you out, you still feel part of everything and you will want your team to win."
When the Spurs players return from international duty they'll take on West Ham in a London derby.