The Scottish champions were handed a lucrative tie against the Italian giants after finishing second in Group G behind Barcelona, whom they beat 2-1 on a memorable night at Celtic Park last November.
That momentous result against the Catalan club, along with a win in Moscow against Spartak during an impressive European campaign to date, gives Boyd confidence ahead of the Serie A side's visit to Glasgow for Tuesday's first leg.
Speaking at a hotel in the city on Thursday, where he was helping ESPN publicise their coverage of the Scottish Premier League, Boyd said: "Since the draw was made, Juventus have stuttered on occasions in terms of some of their performances.
"They will still make it a very difficult game but I think this Celtic team have grown in stature by the way they have played.
"Neil Lennon has got them playing great as a team, great as a unit and they can go into is game with confidence on the back of what they have achieved so far."
While Barcelona are still believed by many to be the best club side in Europe, Boyd believes Juventus could provide stiffer opposition for Neil Lennon's team, who first have to negotiate a trip to Inverness in the SPL on Saturday.
The former Scotland and Motherwell defender said: "Possibly (it could be more difficult), because the expectation level has changed.
"No-one expected anything against Barcelona and Celtic were unlucky away in the Nou Camp (when they lost), but the home leg at Celtic Park was one of the best atmospheres I have ever experienced.
"That might have had an impact that night and it might have an impact against Juventus.
"But Juventus are probably a more structured team defensively.
"Italian football is renowned for that and that might make it more difficult for Celtic to create chances."