West Brom joined Portsmouth, Cardiff and Barnsley in the semi-finals two seasons ago and a place in the final eight is at stake this time around at the Madejski Stadium on Saturday.
But Albion head coach Di Matteo, twice a winner himself with Chelsea and former record holder for the quickest goal ever scored in an FA Cup final, is not getting carried away.
"It's a great competition, the FA Cup in England," he told the club's official website. "We've tried our best in previous games and that's what we'll do on Saturday - we'll try to get through to the next round.
"We'll have to focus on the next game because, if we don't get through, then the bigger teams going out doesn't come into consideration.
"Reading have had a proper cup run, they knocked out Liverpool and Burnley and I think they have picked up in the league as well now as the new manager gets to grips with his team. I'm sure they'll be up for it."
Di Matteo is not wrong.
The Royals are a different proposition since West Brom's 3-1 Championship victory at The Hawthorns back in October.
Brendan Rodgers has been replaced in the hotseat by Brian McDermott, whose achievements as caretaker boss saw him secure the position on a full-time basis.
McDermott has transformed the Royals' fortunes and the outlook is brighter again in Berkshire following three successive victories, which have moved the club to within a point of safety.
But his exploits in the cup have not gone unnoticed, either, with Liverpool and Burnley both put to the sword.
Championship leaders Albion now stand in the way of a place in the quarter-finals for the first time since 1927, and McDermott told Reading's website: "We're really looking forward to it. We should have a good crowd, a special atmosphere and a special day.
"It's been a long time since we got to the late stages of the FA Cup and we'll try to win the game. West Brom will also try to win and I think it will be really good for the fans because of that.
"The FA Cup is a great competition and everyone has memories of it. Now we have our own memories - beating Liverpool at Anfield with Shane Long scoring and then beating Burnley. We want more of it.
"I don't like to talk about giant-killings because we are Reading, we are a big club. We were in the Premier League not long ago and if anyone comes to our place we want them to have to play well.
"My only concern is if we don't perform, especially in front of our own fans. If we do perform, we're in with a good shout."