Mauricio Pochettino insisted it is difficult to succeed without the right tools as he compared Premier League hopefuls Tottenham to Formula One team McLaren.
Tottenham did not sign a player in January – the second successive window without reinforcements having failed to bring in new faces at the start of the season.
Spurs – who are preparing for the Champions League last 16 against Borussia Dortmund – are also without star duo Harry Kane and Dele Alli as they try to keep pace with Liverpool and Manchester City in the Premier League.
Disappointed with the lack of transfer business, Pochettino used an F1 analogy to discuss Tottenham's battle for silverware – highlighting Fernando Alonso's struggles at McLaren, where he finished 11th while Mercedes star Lewis Hamilton topped the standings in 2018.
"We were waiting for different situations that maybe happen or don't like every transfer window," Pochettino said ahead of Saturday's clash at home to Newcastle United, with Spurs third and seven points behind leaders Liverpool.
"I wanted to strengthen the squad but if we cannot sign, I need to stick with the project of the club. If you see the [Premier League] table, we are there, a lot can happen."
Pochettino added: "When you work in football, it's because you want to win. It's easy to be passionate and shout 'I am a winner' but if you don't have the tools to win, it's difficult.
"Fernando Alonso and Lewis Hamilton are the best drivers in Formula One. But if you put Hamilton in McLaren last season and Alonso in Mercedes, it's the same story, Hamilton on the bottom and Alonso on the top. That's the reality.
"I follow Formula One. I love McLaren. But it wasn't competitive last season. That's the reality, no? But do you think that's a problem with Alonso or a problem with the car?
"Also, you can have an amazing car but you can crash after the first bend. You can crash with an amazing car and not win."