City took a big step towards the Carabao Cup final after a 2-0 away victory against the Magpies in Tuesday's (13.01.26) semi-final first leg but the coach was irked by the decision to disallow a goal by new signing Antoine Semenyo after Erling Haaland was ruled to be offside following a VAR check that went on for over five minutes.
Pointing out previous decisions, Guardiola told Sky Sports: "Four officials and VAR are not able to make a decision, they go to the referee first.
"I understand why here in the Premier League, with [Fabian] Schar and the penalty, the VAR didn't say anything. I understand why in the Premier League game here, the penalty for Jeremy Doku from [Malick] Thiaw... Take a look, take a look.
"The second goal [tonight] the line was really perfect, millimetres. That I don't understand but I'm pretty sure the official is going to call me tomorrow and explain why VAR didn't intervene in those two penalties here at 0-0 [in November].
"And I tell you today, look in my press conference and I didn't say anything after that Newcastle game. But today VAR intervened. I was waiting in that moment, two unbelievable penalties and it didn't happen."
The City manager added: "But that's okay. We know how it works and that will make us stronger.
"It's in that situation how we react. It's the semi-finals. We play for a lot to reach the finals. It will make us stronger."
Semenyo did score City's opening goal and Guardiola lauded the immediate impact made by the forward since his £64 million arrival from Bournemouth last week.
He said: "We know Bournemouth did an incredible job with him and every time the ball arrives to him he always is there."