Tottenham manager Mauricio Pochettino said he was disappointed with his side's performance against Manchester United despite winning 3-0 at Old Trafford.
Two goals from Lucas Moura after Harry Kane's second half opener ensured Spurs picked up their first win at United since 2014, but Pochettino said there is still room for improvement.
"My mood wasn't great [after Monday]," he said. "I was so disappointed. I think we need to improve our performance. The first half I wasn't happy and I translated that to the players.
"We need to fight against the perception. When you compare the perception and the reality, we need to talk about the reality, and the reality was in the first half we can concede one, two or three goals.
"Of course the team showed character and in the second half we were much better. I think we dominated and we created the best options.
"But if we want to fight for big things, before talking to you and expressing our feelings to the media and our fans, it's about trying to improve -- and we need to improve because it's only three games from the beginning of the season.
"We're going to play on Sunday against a very good team -- a team that's going to fight and is in a very good moment, After three games they're over the moon.
"If we're not ready and we believe because we beat Manchester United 3-0 that all is fantastic, I think we are going to crash.
"When you've beaten Manchester United 3-0 in Old Trafford, an historic victory, it's easy to say our performance was fantastic and they [United] were not so good.
"But when you watch again the game I think the line was very thin, to be in the left or right, in the positive or the negative. Still in the last three games we've conceded a lot of chances. Our keeper made an unbelievable save to keep the team alive.
"Of course after we scored we showed character and many positives things, but come on. If we want to fight and be a contender, we need to talk on the pitch and not outside. We need to show we are capable after 10 months, not only after three games."
Captain Hugo Lloris will miss their trip to Watford on Sunday with a thigh injury.
"Of course he's going to miss the game against Watford, but we hope for Liverpool he will be ready again," Pochettino told a news conference. "It's not a big issue."
Spurs will also be without Son Heung-Min for the trip to Watford as he prepares to play in the Asian Games final against Japan, and victory would alleviate him of compulsory national service.
"It's a subject that we talk about a lot," Pochettino said. "He was worried and of course he wants to deliver the victory and win because he wants to avoid it, of course.
"If something wrong happens, it's not in our hands now what's going to happen. We'll see what happens. But he's our player. We look after him and we care about him, but we're positive and we hope he can score and win and avoid it, be happy and enjoy his career here with us."
Spurs this week confirmed that they will apply to the EFL to play their Carabao Cup game with Watford at Stadium MK, and sources told ESPN FC their Premier League match with Manchester City is expected to be moved to Monday Oct. 29 in case there are further delays to the construction of their new stadium.
Pochettino said he is empathetic with the fans and their concerns.
"It's for our fans to understand the circumstances of the club," he said. "What can we do? OK, maybe I can go after the press conference and help the builders, but what else can I do? Maybe I could point my finger and say 'there, there, there.'"
Spurs will play at least one Champions League group stage game at Wembley too, and Pochettino is excited after being drawn with Barcelona, PSV Eindhoven and Inter Milan.
"I think when you're going to play PSV, Inter Milan or Barcelona that's like last season, the real Champions League," he said. "With the Premier League, it's the best competition in the world. It's so exciting to face this kind of club, and I come back to my town, Barcelona. PSV is a young team but it's exciting to play there too."