The pair were lavished with praise when Juve got off to a flying start, but their recent below-par performances have contributed to their team picking up just two points from their last three Serie A games.
Former Werder Bremen playmaker Diego earned comparisons with Michel Platini for his performances in earlier wins over Chievo Verona and AS Roma, but has not been so sharp after returning from a hamstring injury.
"Melo has not suddenly become a no-hoper, he's just had a few problems," defender Fabio Cannavaro told reporters. "We know what he's worth."
Cannavaro may return for Juve from a thigh problem having played in Italy's 3-2 win over Cyprus on Wednesday after being cleared of a doping charge earlier this week.
Juve's Mali midfielder Mohamed Sissoko is tipped to play for the first time since breaking a bone in his foot in March.
Genoa's city rivals Sampdoria, who share the top spot with Inter, meet Lazio in Rome on Sunday.
AS Roma, who visit struggling AC Milan in Sunday's late game, will be seeking to continue their good run of results since Claudio Ranieri took over, although captain Francesco Totti is a doubt after taking a knock to his knee.
