It was a redemptive afternoon for the coach and the quarterback, who both showed needed improvement to get the Eagles to 4-5 entering next week's game against the Green Bay Packers.
Foles rebounded from an Oct. 20 loss to the Dallas Cowboys in which he completed 37.9 percent of his passes for only 80 yards before a concussion prompted an early exit.
Starting in his first game since the concussion in place of the injured Michael Vick, Foles finished 22 of 28 for 406 yards and seven touchdowns. Those numbers could have been even gaudier had Kelly kept Foles in the game for more than one drive in the fourth quarter.
Kelly, whose offense failed to score a touchdown the last two games, created mismatches and dictated the tempo throughout the game. He relied on Foles' making quick decisions and throwing accurately - two things Foles wasn't able to do against the Cowboys.
"Sometimes you're going to have bad games, and they're tough to deal with," Foles said. "I saw what I did wrong, and I knew I could fix them by working on them in practice and watching them on film."
Eagles players noted the way Foles appeared in practice throughout the week. He focused on his follow-through and his footwork. He had noticed that his feet were not always in the right spot against the Cowboys, and he needed to be more accurate. Foles finished with a perfect 158.3 passer rating Sunday.
"He just seemed so focused this game, like he had something to prove today," running back LeSean McCoy said.
Kelly has resisted saying what will happen once Vick is healthy. He said again after Sunday's game that the starter would be dictated by health. But it's difficult to envision an Eagles quarterback playing better than the way Foles played in Oakland.
"He played unbelievable," tight end Brent Celek said. "I think the stats speak for themselves. He was great; we knew he has it in him."
Celek said it was one of the best performances he's ever seen. Running back McCoy said the only performance he's seen that compares to Sunday was Michael Vick's against Washington in 2010, when Vick passed for four touchdowns and rushed for two.
Five Eagles caught touchdown passes from Foles: McCoy, Celek, DeSean Jackson, Riley Cooper, and Zach Ertz.
Jackson led all Eagles receivers with five catches for 150 yards and one touchdown. Cooper finished with five catches for 139 yards and three touchdowns.
"That's how the offense usually works," McCoy said. "Past two weeks, we weren't doing well, but before that, we were a dominant offense."
The scoring commenced on the Eagles' opening drive, when Foles completed 6 of 7 passes for 94 yards. The drive was highlighted by a 42-yard screen pass to Cooper and finished with a 2-yarder to Brent Celek.
The onslaught started in earnest in the second quarter, when Foles threw three touchdowns. He hit Cooper for a 17-yard score in the back of the end zone on the second play of the quarter. They reconnected the next time the Eagles had the ball for a 63-yard touchdown down the middle of the field. It was the longest catch of Cooper's career and longest pass of Foles' career.
After a Raiders score cut the Eagles lead to 21-10, Foles responded by leading the Eagles on an 80-yard drive. He found tight end Zach Ertz for the rookie tight end's first touchdown.
Foles became the first Eagle with four first-half touchdowns since Donovan McNabb on Sept. 23, 2007.
By halftime, the game seemed a race for the record book. Foles found the end zone on the first two drives of the third quarter, and the final touchdown came with 4 minutes, 28 seconds remaining in the third quarter. Kelly played Foles two more drives before pulling him for Matt Barkley.
Foles did not break the single-game record for touchdown passes, but he made a convincing statement about his capabilities in Kelly's offense. After the debacle against Dallas, Foles responded with the best performance of his career. Entering next week's game against the Packers, there will be far less concern about Foles' ability - and perhaps even his future - than before Sunday's victory.
"I think that's what we all expected, so maybe he showed some other people," Kelly said. "What happened in the Dallas game was really the exception and not the rule for him."