The Melbourne Rebels were their own worst enemy as they handed the Super Rugby front-running Sharks a 22-16 win at AAMI Park.
The Rebels dominated territory and possession but let themselves down with costly handling errors while penalties helped keep the visitors in the lead.
Melbourne's defence held firm until the 63rd minute when they again turned over the ball and the Sharks counter-attacked and raced downfield, with winger JP Pietersen touching down.
That blew the lead out to 22-9 with their earlier points coming from South African sharp-shooter Frans Steyn, who booted five from five for a 15-6 halftime scoreline.
In their usual fashion, the Rebels, who have won six of their last seven games at home, refused to lay down.