City procured a two-goal advantage after a remarkable first-leg match at the Etihad Stadium on Tuesday.
City procured a two-goal advantage after a remarkable first-leg match at the Etihad Stadium on Tuesday in which they fought back from 2-1 and 3-2 down to put themselves in the driving seat.
Monaco's goals exposed serious failings in the City rearguard, but although Guardiola acknowledged his side must tighten up at the back, he said they would go to Stade Louis II intending to attack.
"They will attack more and more and we have to defend better. But we will have our chances," said the City manager.
"We are going to fly to Monaco to score as many goals as possible. We are not going to defend that result."
"We now know each other better. We will adjust some things, they will adjust some things, but we have to score goals."
"If we don't score a goal in Monaco, we will be eliminated."
Raheem Sterling gave City a 26th-minute lead following a brilliant run from Leroy Sane, but a loose kick by home goalkeeper Willy Caballero enabled Monaco to level through Radamel Falcao's header.
A dawdling Nicolas Otamendi was at fault for Monaco's second goal, scored by Kylian Mbappe, and then conceded a penalty, only for Caballero to save Falcao's effort.
Sergio Aguero and Falcao swapped goals, the former benefiting from a huge error by Monaco goalkeeper Danijel Subasic, the latter scoring with a sublime chip, before City found an extra gear.
Aguero volleyed in David Silva's corner to make it 3-3 in the 71st minute and further goals from John Stones and Sane carried Guardiola's men to a breathless victory.
Aguero was booked for diving after flinging himself over a challenge by Subasic in the first half, but Guardiola refused to discuss the incident, barking: "Next question!"
Aguero has only returned to the starting XI because of an injury to Gabriel Jesus, but he played down suggestions his relationship with Guardiola is frosty.
"The truth is we get on very well," said the Argentine striker.
"What he wants, above everything, from all the players is that we push a little more. He's always asking me for more, more, more."
"Obviously it's a sacrifice I have to make, that we all have to make, and fortunately tonight it worked and we'll see if it keeps working in the next game."
Monaco coach Leonardo Jardim said his team had paid for "defensive errors", but said the "key moment" had been Falcao's failure to convert his penalty early in the second half.
The visitors were 2-1 up when Otamendi was penalised for going through the back of Falcao, but the Colombian dallied over his spot-kick and then saw a tame shot parried by Caballero.
French striker Mbappe, 18, vindicated Jardim's decision to hand him a first tournament start by calmly netting Monaco's second goal after Otamendi had been caught out by Fabinho's free-kick.
Jardim hailed the teenager's display, but said Monaco's defensive shortcomings showed the club's commitment to developing young players was a double-edged sword.
"I used Kylian up front today because we know City well. We know there's lots of space in behind," Jardim told his post-match press conference.
"I thought he played a great match. The little guy is 18 years old. And that's part of our project as well."
"The defensive errors are also a question of age, maturity. Kylian is 18. Lots of the players are 20, 21, 22."
Monaco's performance confirmed their status as Europe's most prolific attacking team and gave Jardim hope they can turn the tie around in three weeks' time.
"I think playing here in England, scoring three goals at City, putting on a great show, is also an important moment," he said.
"I congratulate the team. There are 90 minutes left at home. Nothing is finished."