The table-toppers dominated possession at the Etihad Stadium, hit the woodwork through Kevin De Bruyne and saw two penalties saved by Maarten Stekelenburg - a hard luck story that could have ended in defeat when Romelu Lukaku finished off a rare, but incisive, counter-attack in the 64th minute.
City levelled through substitute Nolito's precise header and might easily have turned a 1-1 draw into maximum points as they searched in vain for a winner.
Koeman is no wide-eyed newcomer to the dugout, having racked up 16 years, four countries and nine clubs as a number one, but he was left groping for superlatives.
"They played fantastic football
They are the best team in my managerial career that I've played against," he said.
"Really high, top pressing, high tempo...we make some mistakes because the pressing was so high.
"If you look to the football, to the offensive style, the movement, the quality of the offensive players, they are in my opinion the best team in the Premier League.
"I'm pleased with a point and we didn't deserve more, I know
Maybe we didn't deserve one when you count the chances and the opportunities, two missed penalties
But football is unpredictable."
While Koeman is not typically given to hyperbole, he had found his groove by the time he came to comment on Stekelenburg, who denied both De Bruyne and Sergio Aguero from the spot.
"Maybe the goalkeeper played his best game ever," he said
"We know he is a good goalkeeper but saving two penalties and maybe two more shots from De Bruyne...you need that luck to get a good result."
Guardiola may be thankful for his former Barcelona team-mate's kind words but he would much rather have been toasting a return to winning ways on Saturday evening.
Having been held 3-3 by Celtic in the Champions League and well beaten by Tottenham before the international break, City are now three games without a win after starting the campaign with 10 on the trot.
Guardiola accepted his team were riding a tricky patch - not an ideal situation heading into a midweek Champions League assignment against his former side Barca.
But he has no intention of compromising his principles on the back of three winless matches.
"I'm sorry, never in my life am I going to change the way I want to play football," he said.
"It's the only way I have
I can make mistakes, be judged for many things, but I have only one power: my teams play the way I want.
"There are storms, problems, but what is nice is to improve on that
We've improved a lot on what happened in Glasgow and Tottenham.
"We created enough chances to win the game, they had one chance
One situation
Sometimes football is beautiful for that reason and sometimes you play bad and win games."
On his side's wastefulness from 12 yards, Guardiola confirmed his side do not work on spot-kicks in training.
"No
I don't have time to practice everything I want to practice," he said.
"I'm not going to talk or discuss the quality of Kevin or Sergio to kick penalties
You can practice in training sessions, but nobody is there, no pressure."
Source : PA
Source: PA