Bulgarian Petrov, 37, made his comeback on Villa's pre-season tour of Austria, just over four years after being diagnosed with acute leukaemia.
"It was really good to see him back out there," Bennett, 26, told BBC WM 95.6.
"He's obviously been through a tough time and I've got a lot of respect for him and you can see, when he's out there, he can still play football."
Former captain Petrov, who retired in May 2013, now has his sights set on making a professional return with the Championship club and has been building his fitness during pre-season with Villa.
He played the second half in Villa's 8-0 friendly win over sixth-tier club GAK 1902 on Saturday.
"He's still got it and I think Stan can play a big part for us this season," Bennett added.
Following last season's dismal relegation from the Premier League, Villa are determined to get back into the top flight as soon as possible under new owner Tony Xia.
New boss Roberto Di Matteo has already spent £3m on Bournemouth defender Tommy Elphick and has also completed deals for Reading youngster Aaron Tshibola and Italian goalkeeper Pierluigi Gollini.
And left-back Bennett, who joined Villa from Middlesbrough in August 2012, says there is a good vibe at Villa Park.
"There's a lot of positivity around the club at the moment with the new manager and owner," said Bennett, who scored from two free-kicks in Saturday's victory.
"We've got a few new players who are gelling well - I think the fans can look forward to a good season."
Bennett made 25 appearances in his first season in the Premier League with Villa but only played five times the following campaign and spent 2014-15 on loan with Championship Brighton.
He spent three months at Sheffield Wednesday last term but is now back hoping to force his way into Di Matteo's plans.
"I want to prove to the manager I can play in this league," Bennett added.
"Obviously there's competition with Jordan Amavi and Aly Cissokho - but you get that at any club and it pushes you to play better.
"Promotion is the main aim - Aston Villa need to be in the Premier League."
Stiliyan Petrov can be a "big part" of Aston Villa's season after his recovery from cancer says defender Joe Bennett.