Mauricio Pochettino claimed the loss of Hugo Lloris to a serious arm injury had a major psychological impact on Tottenham in their chastening 3-0 defeat to Brighton and Hove Albion.
Spurs captain Lloris was given oxygen before being carried from the pitch on a stretcher during the opening stages of Saturday's clash at the Amex Stadium.
The goalkeeper suffered the injury when he spilled a routine cross, stumbled backwards and planted his left arm, which appeared to buckle as he steadied his fall.
Neal Maupay nodded home the loose ball at point-blank range and Brighton went on to add a further two through teenager Aaron Connolly.
The sight of Lloris in agony and a fifth defeat of the season in all competitions capped a demoralising week for Tottenham, who were hammered 7-2 by Bayern Munich in the Champions League on Tuesday.
"I think the news is not good," Pochettino said of the France international, who was taken to hospital.
"We have to wait, the club is going to explain the real situation. Everyone saw on the pitch when he landed that it wasn't a good situation."
He added: "Of course it affected the game. We cannot take the credit from Brighton, but the team suffered a massive impact from that action.
"We tried to find a different way to play in the second half and we didn't have much luck.
"At 3-0 you could see the game was over. I want to say sorry to the fans and thank them for their massive effort."
Tottenham, still seemingly scarred by the result in midweek, offered little resistance after falling behind as they limped to a first defeat to Brighton in 36 years.
Irish forward Connolly was particularly impressive, marking his maiden Premier League start with two well-taken goals either side of half-time.
Graham Potter praised the 19-year-old as he celebrated a pressure-relieving first victory since the opening weekend of the season.
"He's been knocking on the door," Potter told BT Sport when asked about Connolly.
"He's had some substitute appearances and been unlucky not to score. He gives us an extra dimension. I'm delighted for him.
"He's a young lad with a big future and we're delighted we've got him with us."