The Blues' interim first team coach has only lost once since taking over from Andre Villas-Boas in March, and has led the club to the final of both the FA Cup and Champions League.
On Wednesday, they face a Newcastle side that sit just a point above them in fifth place, while Tottenham Hotspur occupy fourth spot after their 2-0 victory over Blackburn Rovers at the weekend.
And Di Matteo has hailed the work of his players having fought they way back into the frame to finish fourth.
"We've been trying very hard to make up the distance between the clubs who are ahead of us and now we are almost on equal points," he told Chelsea’s official club website.
"It was a big effort for us to get to where we are now, and we're in a good position to try and reach fourth spot.
"We always said that this game was crucial. We've tried our best in the league to gain the points we needed. The fact that we've been able to make so many points up is a credit to the players and the team. All the games are important but this is massive for us, although the last two in the league will be as well."
However, the Italian also warned his players about the threat of Alan Pardew's men, adding: "They had a little slip-up at the weekend, but they've won six out of the last seven.
"They're very dangerous on the break, they have big threats up front and players who can score goals, they're a good side.”
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