The 23-year-old took his tally for the season in all competitions to 27 as he combined with the excellent Kevin De Bruyne to deliver a goalscoring masterclass in the 6-2 victory at Kenilworth Road on Tuesday.
It came less than four weeks after his return to the side following nearly two months out with a foot injury, and took his total since joining City in the summer of 2022 to 79 in 83 appearances.
After looking noticeably out of sorts in recent games, particularly during the 1-1 draw with Chelsea at the Etihad Stadium when he missed a host of chances, it marked a devastating return to form for a player who scored a record 36 times in the Premier League last season.
"How many chances did he have against Chelsea?" said Guardiola. "A lot. He maybe had less against Bournemouth (a 1-0 away win), one or two. But it's his talent. We know always he is there, he always has the chances.
"Always we work as a team, providing the chances. Sometimes you score goals, sometimes not. Quite often he scores, but it's not a big issue because he's a special talent.
"The number he has at his age in all competitions, honestly it's unbelievable. At the end, we know it. He's our top goalscorer, happy that he's got the confidence, because the guys who are the top scorers need goals, and he did it against Luton."
Haaland hit a first-half hat-trick to ease his team into the quarter-finals, with each of his goals set up by De Bruyne who himself returned from a lengthy injury lay-off only in January.
The pair combined for Haaland's fourth in the second half after Rob Edwards' side had briefly threatened a fightback via two goals from Jordan Clark.
Bernardo Silva set up the Norwegian's fifth, before a fine finish from Mateo Kovacic made it six as the champions put on an irresistible showing ahead of Sunday's Manchester derby at the Etihad.
"The United game will be completely different," said Guardiola. "They defend differently. They have experienced players.
"We'll have two days off, so people don't see each other. Have to refresh out minds and our legs and have two days to prepare our game."