But Ramsey got the champions back on level terms 10 minutes later on his full debut, with a deflected effort past Verona goalkeeper Marco Silvestri.
Ronaldo put Juventus ahead from the spot with just his second goal this season three minutes after the restart, having missed two chances before the break.
Juve held on thanks to Buffon, who denied Mattia Zaccagni and Lazovic in front of goal after 89 minutes, while Veloso was denied a brace by the post.
“After the Champions League the team was tired, but the important thing was to win. Let’s take these three points and go ahead,” said Ronaldo.
Verona are 12th with four points from as many games.
Cagliari and Brescia are seventh and eighth respectively, with each on six points, after the Sardinian side saw off Genoa 3-1 on Friday and newly-promoted Brescia snatched a tight 1-0 win at third-from-bottom Udinese.
Carlo Ancelotti’s Napoli travel south to promoted Lecce on Sunday after seeing off European champions Liverpool 2-0 on Tuesday, while third-placed Bologna can join Juve on 10 points with a win over mid-table Roma.