When the Blues visited The Hawthorns last season, it proved to be Andre Villas-Boas' final match in charge as he was sacked after a 1-0 defeat.
Di Matteo subsequently took the helm, initially on an interim basis, for his first managerial post since being dismissed by West Brom.
He has enjoyed great success in his first few months in the job and Brunt is happy to see the Italian prospering at Stamford Bridge.
"What a great job he's done since he took over. When they came here last year and we won 1-0, obviously the manager got sacked the next day and they weren't doing too well," Brunt told Sky Sports News.
"But they have picked it up since then and obviously got a lot of good results, winning the Champions League and the FA Cup.
"He's a good guy, Robbie. I always got on very well with him and a lot of the lads will tell you the same thing.
"I'm delighted he is doing well."