City were well below their best and indebted to a late save by substitute keeper Stefan Ortega before Erling Haaland bagged his second goal of the game to finally seal a crucial victory with a stoppage-time penalty.
"We were happy in the locker room but they know it's not done, they know it will be tough on Sunday," said Guardiola, whose side are two points ahead of Arsenal heading to the finale of a neck-and-neck title race.
"We have to win a game to do something no team has done."
City face West Ham United at home on Sunday knowing that with Arsenal hosting Everton, only a win is likely to be enough to capture a sixth title in seven seasons.
While City sparkled in the sunshine at Craven Cottage on Sunday during a 4-0 rout, they were strangely subdued at Tottenham's new stadium where until Tuesday they had never scored a Premier League goal.
Guardiola said the enormity of what they are playing for - becoming the first team in English history to win four titles in a row - had weighed heavily.
"They were playing for the consequences of the result (in the first half)," Guardiola, told reporters. "When you do that you are going to lose the Premier League. You cannot perform to your level. They are human beings, I understand the pressure.
"Not even Arsenal played well against Manchester United, they knew if they did not win there they would not win the Premier League.
"It will be the same on Sunday for us against West Ham. We will feel the pressure. Look at Aston Villa a few seasons ago, 2-0 down with 15 minutes to go, Sergio Aguero against QPR, went to 93 minutes. It is normal. That is why we talk and say everyone has to relax themselves and do what they have to do, that is all."
Former Tottenham defender Kyle Walker echoed Guardiola's words, saying emotions had been riding high.
"We prepare, we recover and West Ham is another final and hopefully we can go and make history for this great club," he told Sky Sports. "It is not job done by a million miles.
"Hopefully we can get the win. If I didn't enjoy the pressure, I would be in the wrong job and the wrong team."
