Shanahan heaps praise on Mullens: 'He's a machine in there'

San Francisco 49ers third-string quarterback Nick Mullens was the star of the show Thursday night, lighting up the hapless Oakland Raiders in his first career start and propelling his team to a dominant 34-3 win.

Mullens put up record-setting numbers, throwing for 262 yards and three touchdowns on 22 attempts for a near-perfect passer rating of 151.9, the highest mark for a debuting quarterback since 1990.

Kyle Shanahan was the mastermind behind Mullens' huge night, and the 49ers head coach wasn't surprised the bright lights of prime time had no effect on the 2017 undrafted free agent.

"You never know until you see someone," Shanahan said about Mullens, according to NFL.com's Austin Knoblauch. "He didn't surprise us in terms of, the game's not too big for Nick. He's very poised. He is always locked in. The guys, they respect him. He earned a lot of respect in the preseason, them watching him play. Both years, last year and this year.

"The way he handles himself in practice each week. He didn't really know for sure whether he was going to start today, until today, and just the way he handled the two days of long walkthroughs and stuff.

"He's a machine in there and I was happy for him."

Despite the performance, Shanahan didn't say if he will continue with Mullens as the starter. C.J. Beathard - who started the previous five games - was forced to act as the backup as he dealt with wrist and thumb injuries that made him unable to properly grip the football.

"We'll consider it," Shanahan said. "Definitely not thinking about that right now, but our whole team played very well. Nick definitely did. ... It's good to get a win today and hopefully it can lead to some others."