The Brazilian playmaker, who moved from Werder Bremen in the close season, laid on the winning goal in his debut against Chievo Verona on the opening day and then scored twice as Juve maintained their perfect start with a 3-1 win at AS Roma.
Those performances have led to comparisons to imported past masters such as Zico, Michel Platini, Zinedine Zidane and fuelled hope among the Turin side's fans that they have the player with the quality needed to surpass champions Inter Milan.
"I knew Diego was good, but even I didn't expect a player with such strength, skill and technique," coach Ciro Ferrara told reporters. "He's surprising me."
While the 24-year-old's sweet right foot, speed and ability to beat opponents have won plaudits, what has really impressed fans and fellow players is the determination and character he has displayed.
Some pundits have even dared to point out that, while Platini and Zidane took some time to get the measure of the highly tactical Italian league, Diego has had an instant impact.
But Ferrara has warned against getting carried away.
"It's only beginning," he said. "Let's not weigh him down with too much responsibility."
Ferrara may rest some regulars in Rome this weekend in view of Tuesday's Champions League game against Girondins Bordeaux after seven of his men played in Italy's 2-0 win over Bulgaria in Wednesday's World Cup qualifier.
Lazio are upbeat after they too won their opening two games to share the top spot with Juve, Genoa and Sampdoria.
But the hosts may be without in-form Argentine Mauro Zarate, who has a leg problem, while fellow forward Tommaso Rocchi also has a knock.
AC Milan, who have three points from two games, will want to improve from the 4-0 drubbing they suffered in the derby against Inter when they visit Livorno earlier on Saturday.
On Sunday Inter entertain promoted Parma, who, like the champions, have four points.
Roma's visit to Siena on Sunday will be their first match under former Juventus and Chelsea boss Claudio Ranieri after Luciano Spalletti quit following two defeats in as many games.
