Ilkay Gundogan’s first-half brace and goals from Joao Cancelo, Riyad Mahrez and Raheem Sterling eased City to victory at The Hawthorns.
They are a point ahead of Manchester United, although their rivals can reclaim top spot with victory over Sheffield United on Wednesday.
City are the ninth team to top the table this season but, after an 11th straight in win all competitions, Guardiola is keeping his cool.
He said: “The last thing I’m thinking of is the table. Now I want to come back home safely, have a few days off and Sheffield United is all I’m concerned about.
“We still have 19 games to go in this incredible marathon. We are going to drop points and lose games but the important thing is to be calm, like we were when we were 12th in the table and understand why we didn’t win that game and immediately win the next one.
“This is all I’m concerned about now. It’s the Premier League, welcome, it’s so tough for everyone. You know it’s competitive but we have had a good run.
“Congratulations to the team, we could not leave our box for the first two or three minutes but the rest of the game was good.”
Phil Foden had already hit the post before Gundogan collected Cancelo’s pass and found the bottom corner after six minutes.
Cancelo made it 2-0 on 20 minutes, firing in from the edge of the box with the goal given after a VAR check. Bernardo Silva had been incorrectly flagged offside by Sian Massey-Ellis in the build-up, meaning several Albion defenders had stopped playing.
It was 3-0 after half an hour when Gundogan grabbed his second, pinching the ball from Romaine Sawyers and breezing past Dara O’Shea to score.
Guardiola added: “He has always showed this level, except in the first season because he had an ACL. He has always showed an incredible personality. He is generous and a very nice guy.”
Even without the injured Kevin De Bruyne, City were never troubled and Mahrez added a fourth in first-half stoppage time after Sterling’s searching pass.
Rodri struck the bar from distance after the break and Sterling wrapped up the scoring in the 57th minute when he tapped in Mahrez’s cross.
It was another sorry night for the second-bottom Baggies, who have now conceded 22 times in their last five home games.
Sam Allardyce has overseen four of those matches – shipping 17 without reply – and Albion are six points from safety ahead of Saturday’s showdown with drop rivals Fulham.
“A few home truths needed to be said, it had to be done now because there’s a short period of time before the next game,” said Allardyce, who held a dressing-room inquest for almost an hour after the game.
“These next two games (Fulham and Sheffield United) really stand high in what we need to do. I needed to get my feelings to the players out of the way. They needed to air their views, which is fine as we are all in it together.
“I was disappointed in the performance and to get it out the way means we can learn from it and we don’t see it again. I can accept defeat but not like that.
“What will determine our fate comes in the next two games. A win and a draw is the least we have to try to get.
“We have got to work out what it is, playing at home. There’s no pressure from the fans so we have to work out what.”