Former Chelsea and England midfielder Joe Cole questioned Tottenham's transfer business after their spend of about £302m.
After Sandro Tonali, £85m went on bringing in Mateus Fernandes from West Ham. The Portuguese midfielder was subbed at half-time and Roberto de Zerbi said he "didn't like" Fernandes' performance, while £75m was spent on Savio from Manchester City.
Omar Marmoush will cost £60m once his loan becomes permanent, but Spurs need their big-money buys to prove their worth and perform sooner rather than later.
"Spurs are dominant, chances, and you felt the tension growing - all of a sudden Spurs were just wanting to get to half-time. Once you defend with anxiety, things happen," Cole told TNT.
"When these things go against you, they go against you. Van de Ven going off was a factor, they didn't deal with it well. When you are anxious you make rash decisions.
"Villa defended well but didn't deserve to go in a goal up, and then this place deflated.
"They are not picking up points, a club flirting with relegation two years in a row, I feel they have overpaid for every player they bought this summer - you can't rule them out from being in and around the relegation battle."
De Zerbi, though, defended Tottenham's summer window spending despite their current malaise.
"I am happy with the squad, but the market was long, the situation changed many times," he said.
"There was also financial fair play and we have to respect that. We didn't sell the players we thought there was a possibility to sell.
"The club and the coach, we are not sleeping, we know the characteristics of the players. If we didn't make any different decisions it was because we couldn't."