Erling Haaland netted his 23rd career hat-trick as Manchester City came from behind to eventually beat Ipswich Town 4-1.
Kieran McKenna's side took a shock lead through Sammie Szmodics on seven minutes but the champions soon clicked through the gears, albeit they were given some help from some poor Ipswich decision making.
As little as nine minutes after the Szmodics opener, Man City were 3-1 up.
Leif Davis appeared to have got away with a challenge on Savinho, but VAR David Coote sent referee Sam Allison - promoted from fourth official after Michael Salisbury sustained an injury in the warm-up - to the monitor and Haaland stroked home the penalty.
One became two moments later when debutant Arijanet Muric was dispossessed just inside his own box by Savinho, who found Kevin De Bruyne who passed into the empty net.
- As it happened: Man City 4-1 Ipswich
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Muric's head must've been still blurry as just a minute later he darted out trying to cut out a De Bruyne pass, only to see Haaland nod the ball beyond him and finish from a tight angle.
The Ipswich crossbar was then rattled by Rico Lewis and De Bruyne as City threatened a fourth.
Ipswich defended with good organisation after the break and Guardiola turned to his bench, with chants of "Gundo's coming home" filling the air as Ilkay Gundogan was introduced alongside Jack Grealish with 19 minutes remaining.
Haaland claimed the match ball in the 87th minute when he turned on the edge of the box and powered home a low finish.
Having also scored against Chelsea in the season's opening game Haaland now has 67 goals in 68 Premier League appearances, and 94 in all competitions since joining City.
Opta stats: Four shots, four goals
- Each of the first four shots in this game were scored - marking the first ever time that this has happened in a Premier League game (excl. own goals) on record (since 2006-07).
- All seven of Haaland's Premier League hat-tricks have been scored at the Etihad Stadium - only Thierry Henry has scored more in the competition with 100% of them coming at a single venue (8 at Highbury).
- De Bruyne has both scored and assisted in 26 Premier League games, the most of any Manchester City player in the competition. Meanwhile, only Mohamed Salah (31) has done so on more occasions since De Bruyne's top-flight debut for Man City in September 2015.
Pep: Haaland is ridiculous
Manchester City boss Pep Guardiola: "He [Haaland] feels better than the previous seasons - not having too many holidays. I remember him saying he was tired and drained. This season he's arrived really well. Of course he can't play every game but the goals he scores is unbelievable.
"He did it in Salzburg. He did it in Germany. It's ridiculous. He can compete with Ronaldo and Messi with his goals. We are happy to have him and be here for many years.
"The body language is still there. When defending set pieces and attacking the first action - it is still there. The season is long and we'll be up and down but everyone is committed and ready to do it."
McKenna: Big lessons for us to learn
Ipswich boss Kieran McKenna said: "We got off to a fantastic start, scoring in transition - exactly the type of goal we wanted to score with their line being high. The game was lost in a five minute spell where there are some big lessons for us to learn.
"The first goal isn't in a dangerous situation but being disciplined is so important. The base was there and everyone was comfortable in the plan we came with and how we executed it in the first few minutes. But the goals changed the game completely. What was important at 3-1 was to get back in the game and stay resilient. In the second half we defended well as a team.
"In my eyes we had a clear penalty and should have gone in at half time at 3-2. It's hard to understand how it wasn't given especially with the intervention on the first goal."