But, he need not to have anxious as West Brom's lone strike through a Jay Rodriguez's header from a Nemanja Matic's poor clearance in the United's vital area finally handed them their third title in seven years.
United delayed City's coronation as league champions when they came from two-goal down to win 3-2 at the Etihad Stadium last weekend.
Although United have had a decent season and have beaten every single team, including City, at least once in the Premier League, their cross-town rivals have been more consistent.
West Brom's caretaker manager Darren Moore spoke to reporters after his side's superb 1-0 win against Manchester United yesterday, and disagreed with Jose Mourinho's claim that the visitor's only real threat was from set plays, as quoted by the Express & Star.
"Everything was slow, everything was one more touch, one more flick, one more trick, one more turn, ball lost and no continuity or fluidity in our football". As I was saying: this is a very hard league and all the top-six teams, we knew in advance that two of them would be outside the Champions League positions.
Sergio Aguero has led the way in front of goal
"The amount of goals (93), chances, points, to do that in the Premier League with the contenders that we have, it is because the players are so, so good".
A draw in that game would effectively confirm City as champions as well - it would leave United 15 points behind with five games remaining, while Guardiola's side also boast a far superior goal difference.
"We did not deserve to lose, we gave them opportunity to win the match".
"He told them be careful it is going to be different against West Brom and I go back to Pogba: why didn't you and the rest of the team do what you did against City all season?"
"I'm not trying to explain anything here, or to make an excuse, I just want to keep this weekly meeting with you, although in days like this one it's complicated".
But Tottenham manager Mauricio Pochettino admitted that they deserved to get nothing from the City game.