They are among the bottom three in the league table after defeats by Manchester City and north-east rivals Middlesbrough in their first two league matches.
"David (Moyes) is definitely the man to get it right," South African Pienaar told British media.
"You can't forget he's only come into Sunderland in the middle of pre-season. He's still getting used to the players here and he's got a lot of young players but he will definitely build a solid foundation.
"He's definitely a safe pair of hands. And, at Everton, he often tended to start seasons slowly but finish strongly."
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Moyes, who replaced Sam Allardyce at Sunderland in July, had earlier warned fans to expect a relegation battle for the fifth-season running.
Pienaar would like to see his team mates show the kind of faith in Moyes that the manager had shown in him by signing him.
"We have to try to push away from that mentality of only just avoiding relegation every season," Pienaar added.
"That's a big problem here at the moment. We have to kick on. The manager wants to instil confidence in the players, and he wants the players to just go out and enjoy their football.
"At the moment there are a lot of young players so it will be hard, it might even be a hard season but we will make progress."
Sunderland travel to the St Mary's Stadium to face Southampton in their next league fixture on Saturday.
(Reporting by Nivedita Shankar in Bengaluru; editing by Amlan Chakraborty)
