Thomas Frank slammed 'unacceptable' Tottenham Hotspur fans after their Premier League defeat to Fulham on Saturday. The fans at the Tottenham Hotspur Stadium booed goalkeeper Guglielmo Vicario after his howler helped Fulham take a 2-0 lead within the first six minutes of the match. Spurs are now winless in their last four games across all competitions and have lost three in a row.Tottenham have won just one out of the six matches they played in November, which includes one draw and three losses in the Premier League. Their only win this month came against Copenhagen in the Champions League. Spurs headed into the Fulham clash after conceding nine goals in their last two matches against Arsenal and Paris Saint-Germain. They hoped to regain some confidence by beating London rivals Fulham at home, but they were off to a disastrous start as Vicario's howler helped the visitors take a two-goal lead at the start of the match.The Spurs shot-stopper was punished by Fulham after going walkabout in the build-up to the second goal as Harry Wilson doubled his team's lead after Kenny Tete broke the deadlock in the fourth minute. Mohammed Kudus then pulled one back for the hosts around the hour mark but the Cottagers eventually walked away with the crucial three points. Vicario was jeered at by the home fans after his costly mistake led to Fulham's second goal, as the goalkeeper was booed while the match was going on. The gesture of the fans did not impress the manager as he told Sky Sports: “I didn't like that our fans booed at him [Vicario] straight after and a few times he touched the ball. They can't be true Tottenham fans because everyone supports each other when you are on the pitch. And we do everything we can to perform. After, fair enough, boo, no problem. But not during. That's unacceptable in my opinion."Taking responsibility or the second goal, Vicario addressed the Spurs fans as he told Sky Sports: "The second goal was a mistake of mine, I take responsibility for that. The intent was to clear the ball long and I just hit the ball in a bad way. It was an even bigger mountain to climb. I’m a big man, what can I say? We cannot be influenced by the situation in the stands. The fans have the right to do what they think. It's on us to stay more calm, to focus on ourselves. We are lacking in composure and calmness to overturn results. Today is a bad defeat and it's tough to accept."Spurs started the 2025-26 campaign on a bright note under Frank after a forgetful 2024-25 season. But the sudden dip in form, which saw them collect just one point from their last four league clashes, has seen them drop to the 10th position in the Premier League table.Frank was brought in place of Ange Postecoglou to bring organisation and a calmer head to a young team. However, so far in the season, the team has continued to struggle. The manager, who made Brentford a real force in the English top-flight, has his work cut out in the next couple of months to turn things around at the north London outfit, although the club do not have any plan to part ways with the Danish manager. According to The Telegraph, the club's owners, the Lewis family, are targeting long-term success under the Dane, which suggests that no short-term decisions are being considered. They next face Newcastle United in a difficult Premier League fixture on December 2.