FOXBOROUGH, Massachusetts — It's hard enough to defend Tom Brady with a healthy secondary.
Jacksonville tried to do it Sunday with a backup cornerback at safety and an undrafted rookie quarterback seeing time at corner.
Brady threw for two touchdowns, including the 400th of his career, and the defending Super Bowl champions ran away from the Jaguars 51-17 on Sunday.
It was the most points ever allowed by Jacksonville (1-2).
"Obviously, we are playing against an elite football team and the best quarterback in the league," said linebacker Paul Posluszny. "But we also made a ton of mistakes on our own."
The Jaguars started the game without injured safety Johnathan Cyprien and backup cornerback Dwayne Gratz. Safeties Sergio Brown and Josh Evans left with injuries in the first half.
Peyton Thompson moved to safety, calling the signals for the secondary. Rookie Nick Marshall, the former Auburn signal caller, was also pressed into duty.
"It's the hardest thing to do. We only had three safeties that were active and two of them got hurt. That means a corner is going to play safety," cornerback Davon House said. "You are going to play safety and you ain't never even practiced that position? That's tough man."
The Jaguars were coming off a 23-20 win over Miami and said they considered this a measuring-stick game.
Coach Gus Bradley said they just didn't measure up to the best team in the league.
"When you play against a really good team, you really see the importance of precision," he said. "We didn't play with that."
The Jags were down just 13-3 and driving at the end of the first half when Blake Bortles was intercepted by Devin McCourty. The Patriots (3-0) went downfield and Brady completed a 1-yard TD pass to Danny Amendola just before halftime. The rout was on.
Brady became the fourth quarterback in NFL history to throw for 400 touchdowns, and he added his 401st, a 13-yard pass to Keshawn Martin late in the third quarter.
By that time, it was 37-10.
In all, Brady completed 33 of 42 passes for 358 yards while leading New England to scores on all nine of his drives. Backup Jimmy Garoppolo came in to kneel down on the final possession.
Bortles ended up completing 17 of 33 passes for 242 yards and two scores.
The biggest highlight for Jacksonville was a 59-yard catch and run from Bortles to Allen Hurns that made it 30-10 midway through the third quarter. Jacksonville's other touchdown came on a 6-yard pass from Bortles to Clay Harbor.
Jacksonville also fumbled its first scoring drive.
The Jaguars were facing a third-and-7 in the second quarter when Bortles was hit by Patriots linebacker Jamie Collins on the Patriots 31-yard line.
Collins hit the ball just as Bortles was attempting to pass. The ball sailed forward, bouncing to the Patriots 17, where Jaguars running back Toby Gerhart jumped on it. The officials ruled the play a fumble, and the Patriots unsuccessfully challenged the call.
A few plays later, Jason Myers hit a 40-yard field goal, capping a 17-play drive that took more than eight minutes off the clock and cut the Patriots' lead to 10-3.
"I don't think we can get too down about this game," said wide receiver Allen Robinson, who had four catches for 68 yards. "It's Week 3. We've got a lot of weeks ahead of us."
Rob Gronkowski caught four passes for 101 yards for the Patriots. LeGarrette Blount ran for 78 yards. Julian Edelman caught eight passes for 85 yards.