OAKLAND -- Clelin Ferrell's rookie season has had some growing pains. The No. 4 overall pick lost weight, has been forced to play all along the defensive line and hasn't been putting up the pressure numbers some want to see out of an edge rusher drafted highly.

Jon Gruden and the Raiders have been confident in Ferrell, and rightfully so, touting his impact against the run and noting that not everything is about the sacks, pressures and hits. The game has layers, and Ferrell, who was a star at Clemson, is doing everything they asked. Those numbers would come.

Come they did, and in a wave Thursday night. Down to seven healthy bodies on the defensive line, the Raiders needed big production out of Ferrell and fellow rookie Maxx Crosby in order to fluster Chargers quarterback Philip Rivers.

In his best NFL game to date, Ferrell racked up eight tackles, 2.5 sacks, five pressures, two other tackles for loss and a pass defensed in 56 snaps during the Raiders' 26-24 win over the Chargers.

"Sack totals are driving me nuts," Gruden said of Ferrell after the win. "He does a lot more than just rush the passer. He made some great plays against the run. It was a signature game for him obviously, but it's great for him to get some sacks. Maybe some of the people who are counting sacks out there will acknowledge this."

Raiders safety Erik Harris doesn't understand the pressure that comes with being the No. 4 overall pick. He went undrafted out of Division II California University of Pennsylvania, but he scratched and clawed to get his NFL opportunity. So before the Raiders' Week 8 loss to the Texans, Harris had a talk with Ferrell.

"Clelin and I, we had a talk in Houston about, just about life and in general," Harris said Thursday. "I'm so proud of him. I've never been drafted, especially that high and I couldn't imagine the pressure one would have to perform. I'm just really happy for him. I'm happy he's playing free and doing his job and getting after it.

"I don't know if he was getting frustrated or not. I was just trying to instill confidence in him and just remind him why he was picked where he was picked. He's a great player and sometimes the pressure outside the locker room or even within the locker room that you have to perform and guys are looking at you to perform, it can be a lot of pressure. He's young and he's stepping up and that's why he was No. 4 overall.

"I'm really proud of him for stepping up and having confidence in himself and starting to find his groove within this league."

Despite the NFL learning curve, Ferrell has remained confident in himself, knowing he has the ability to be a difference-maker in this league.

"I feel like any player knows that to become a great player, you have to become it first, you know what I mean?" Ferrell told NBC Sports Bay Area. "You can't just be it. Some guys, they hit bigger jumps than others at times, but it's just going to take time. Trust me, ain't nobody have more confidence in myself than I do."

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The confidence came through Thursday night early and often with Ferrell making life miserable for Rivers along with Crosby. On the Chargers' first drive, Ferrell used his strength to drive left tackle Russell Okung back and grab Rivers, allowing Crosby to finish him off.

Then, he whipped Trey Pipkins in the third quarter and hammered Rivers, mimicking reeling in a fish after the sack.

Ferrell had no desire to talk after the game. He let his play do that through four dominant quarters against a division rival.

The statement was clear: Clelin Ferrell has arrived.