It's been a sluggish start for the Arizona Cardinals, who currently sit at 2-3 after beating the San Francisco 49ers last night. One of the few bright spots through the first five weeks has been the strong running of David Johnson.

Following up on an impressive rookie campaign, expectations for Johnson were sky-high heading into this season. He has not disappointed.

With Carson Palmer ailing from a concussion suffered against the Rams on Sunday, the keys to the car were handed to Johnson. A solid running game is the best friend for a quarterback, let alone a backup like Drew Stanton.

Johnson proceeded to run all over the 49ers' defense, racking up 157 rushing yards and a pair of touchdowns.

After the game, Johnson wasn't shy when discussing how he feels carrying the pigskin.

From ESPN's Josh Weinfuss:

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I feel unstoppable, basically,” Johnson said. “Especially with the help of the guys blocking, the tight ends, the receivers and, obviously, the O-line. It helps me get going. It helps me get into the flow of being able to break some of those tackles, being able to get the yards that we needed.”

Future Hall of Famer Larry Fitzgerald, who scored two touchdowns as well, had nothing but praise for Johnson's play:

“Dave, you know, he’s the catalyst,” Fitzgerald said. “He makes it go offensively. When he starts getting his groove, teams start coming down into the box. It gives us opportunities to make some plays behind the defense in the passing game.”