The imperious Premier League leader outclassed the Championship promotion hopeful at the Liberty Stadium, where they eased to a 15th consecutive win – a record for an English top-flight club.
City's latest dominant victory saw them better runs of 14 in a row set by Preston and North End in 1891-92 and Arsenal in 1987, keeping them in contention for to win silverware on four fronts.
Kyle Walker opened the scoring in the first half before Raheem Sterling slotted in his 12th goal of the season early in the second half and Gabriel Jesus finished brilliantly a few minutes later.
Morgan Whittaker pulled a goal back with a sweet left-footed strike after City's Spain midfielder Rodri limped off with an injury, which Guardiola is hopeful is not serious.
The City boss was full of praise for his players after the juggernaut rolled on in Wales.
Asked about setting the record, the former Barcelona and Bayern Munich boss said: "It is a message for ourselves. We came to win, that was the most important thing.
"We cannot deny how pleased and how proud we are to break this record from a long time ago. Records are there to be broken.
"It is not easy in the modern era to do 15 games in a row. We are happy for our club."
Guardiola said: "I had a feeling that they would create chances, they were dangerous up front. They were so aggressive but we controlled the game and we created a lot of chances but could not convert."
The Spaniard did not appear too concerned about Rodri's injury and revealed Ruben Dias was absent due to illness, while Fernandinho did not feature as he has been troubled by a quad niggle.
Guardiola will be hoping they will recover in time for a Premier League encounter with Tottenham at the Etihad Stadium on Saturday.