The Baggies struck twice in each half of an eventful clash at Goodison Park to end a run of five games without a win with a convincing 4-1 success.
Paul Scharner opened the scoring before Chris Brunt doubled the advantage with a brilliant free-kick.
Tim Cahill pulled one back but West Brom took advantage of the sending-off of Mikel Arteta to secure victory through Somen Tchoyi and a Youssouf Mulumbu effort which was deflected in by Sylvain Distin.
Di Matteo said: "There were some excellent goals today - we were very clinical, which has been missing in the last few weeks from our game.
"I thought we played some fantastic football, we didn't show any fear.
"We showed a lot of courage to come here and play the football we did.
"We rode our luck a bit at 2-1 and our keeper made some great saves to keep us in the game.
"But the quality of our play and the quality of goals gave us our advantage."