By this point, Albion had hit the woodwork once and Phillips did so again before doubling the lead in the third minute of first-half stoppage time to cap an impressive performance.
Although Ben Brereton Diaz was gifted a goal to halve the deficit early in the second half, the Baggies should have won more handsomely and would have done but for Rovers goalkeeper Thomas Kaminski and the woodwork denying them twice more.
However, Albion made it three wins successive wins to remain in the top two and registered their first win at Ewood Park since December 2011.
Ismael said: "(It was a) great performance from Matt.
"I think, since I've been here, he will have a massive part (to play), especially (in) the new position as a nine and it's important to get the rewards.
"He works hard all the time. He missed 10 days due to the virus and now he's getting better and better.
"We wanted more physicality in the number nine position and he did the job perfectly. He scored a goal, he gave us a lot of possibility to play in the pocket.
"Today, we had 23 attempts on the goal, two times (hit the) crossbar, two times (hit the) post. We are on the way with our offensive game and we were strong.
"The mentality, the togetherness we showed already will be a massive part for the rest of the season.
"I think it's great for the guys that we only win games when we work hard together. It's about the work ethic we put in our training sessions and this is the reward. This is a massive win with the right attitude from us."
Blackburn's three-match unbeaten start is over after they lost a league game at home for the first time since April and boss Tony Mowbray was frustrated by the 'embarrassing' start his team made against his former employers.
He said: "We gave them a goal, laid it on a plate for them.
"I thought over the 90 minutes, we matched them up physically, which you have to do against West Brom because there's no more direct team in the league.
"We fought and had a go, and yet we've given them a goal start so we're left frustrated and disappointed. But particularly second half, we more than matched them.
"We try and get (Sam) Gallagher wide, drop it on him and play from there, if he wins his header…we get our chance.
"But we didn't get the first ball out to Gallagher and they got to the edge of our box and we're on the back foot straight away. A few scuffed clearances and it was in the back of our net.
"An embarrassing start to the game, really poor start. But over the 90 minutes, we competed.
"(I'm) frustrated to lose a goal with the last kick of the first half, but everything else in between and the second half, we competed very well against a team that undoubtedly will be at the top end of the table."