A frenetic game at Saint James' Park in the Premier League saw Ilkay Gundogan give Man City a fifth minute lead but Eddie Howe's side hit back with three goals of their own to take a commanding lead.
But Erling Haaland brought City within one of their hosts with his third Premier League goal of the season in the 60th minute before Kevin De Bruyne fed Bernardo Silva with a sumptuous pass to equalise four minutes later.
Although the champions could not find a winner, Guardiola was impressed with how they mounted a comeback and pointed to the difficulty of the division as evidence.
"The team showed who we are," he told BBC Sport. "[It was a] proper football game. We started really well, [then] we lost some duels. Once the game was open, they were better.
"We should [have] taken more time in the final third. [But] that atmosphere after the game - that is what football is all about.
"We could have not won today," he added on Sky Sports. "Newcastle are becoming one of the toughest opponents, for sure. To see the team fight to the end is enough.
"Leeds beat Chelsea today [too]. The Premier League is so difficult for everyone. It shows how amazing [we have been] for five years, and how difficult it will be."
