SOUTH BEND, Ind. (AP) — If Chase Claypool and Ian Book continue connecting as they did Saturday in No. 16 Notre Dame’s 52-20 rout of No. 21 Navy, the hotel roommates may deserve a penthouse suite.

Claypool caught four touchdown passes to match a school record and Book threw five for the third time this season as the Irish (8-2, No. 16 College Football Playoff) won their third straight game.

“The chemistry with Ian has definitely helped a lot,” Claypool said. “I think trust is a big thing. I think he truly trusts me now. Not that he didn’t before, but he knows exactly where to put the ball. He’s throwing the ball up and giving me a chance to make a play.”

Claypool caught seven passes from Book for 117 yards and now has 49 receptions for 768 yards this season.

“Chase is an important part of our offense, so he’s going to get the football,” Irish coach Brian Kelly said. “He was outstanding. We executed flawlessly in the first half against a really good Navy team.”

The 17th straight home victory did not sell out Notre Dame Stadium. It was the first time since 1973 Thanksgiving Day against Air Force, a string of 273 sold-out games. A crowd of 74,080, 3,542 below capacity, saw Notre Dame win for the 79th time in the 93-game series that has been played continuously since 1927.

Book completed 14 of 20 passes for 284 yards and five touchdowns before exiting midway through the third quarter and the Irish up 45-3. It was his third game with five touchdown passes this season and followed a 38-7 victory at Duke in which he rushed for 139 yards and threw for four touchdowns, a Notre Dame first.

“I think we can safely assume he is the guy we thought he would be,” Kelly said. “He started slowly but has now found himself. He is the leader of our offense and our offense is playing at a high level now.”

But Book turned the high praise toward his wide receiver.

“Chase is having an awesome year,” Book said. “It’s starting to show on Saturdays by how hard he’s working in practice.”

Claypool had scoring receptions of 7, 47 and 3 yards from Book to give the Irish a 21-0 lead early in the second quarter. Book threw a 70-yard touchdown pass to sophomore Braden Lenzy later in the quarter as Notre Dame took a 38-3 halftime lead and then hit Claypool with a 20-yard scoring pass on their final play of the game together. Claypool’s TD haul matched Maurice Stovall, who caught four TD passes against BYU in 2005.

The loss ended a five-game winning streak for the Midshipmen (7-2, No. 23 CFP), who entered leading the nation in rushing with 357.9 yards per game.

“We got our butts whipped and it started with me,” Navy coach Ken Niumatalolo said. “They had a great plan on both sides of the ball and we just got a total butt-whipping.”

The Irish defense forced three first-half fumbles by Navy’s shifty quarterback Malcolm Perry, who rushed 25 times for 117 yards before behind replaced in the third quarter by freshman Perry Olsen.

Irish defensive end Khalid Kareem forced two fumbles and linebacker Drew White had 10 tackles. Notre Dame turned four fumble recoveries into 24 points.

THE TAKEAWAY

Navy: Perry was averaging 130.2 rushing yards entering the game. He managed a 46-yard run late in the first half that set up a Bijan Nichols’ 27-yard field goal, but for the most part was contained. Meanwhile, the Midshipmen’s defense, allowing just 310.6 yards a game, allowed 300 at halftime by the Irish and 410 for the game.

“We had to play almost perfect to beat these guys and fumbling doesn’t help you beat anybody, and I take full ownership of that,” Perry said.

Notre Dame: After throwing incomplete on his second attempt, Book completed 10 passes in a row. He also added 31 yards on five carries.

“I feel great,” Book said. “I’m confident with all the guys on this team. The defense is doing an outstanding job getting us the football. Our offense is starting to roll. it’s awesome.”

NOT HIS BEST GAME

Claypool’s four touchdown receptions may have tied the school record, but they weren’t his most ever in a football game. He once caught 10 TDs in an eighth-grade game.

“It was against our rival, the No. 1 team in the league,” Claypool said. “They ran a triple option, similar to this team (Navy), so we knew every possession we got was going to be important. We just had a good game plan and I ran around a little bit.”

R-E-S-P-E-C-T

In addition to standing for each other’s alma maters afterward, another poignant moment came when Niumatalolo and Irish safety Alohi Gilman shared a postgame handshake and hug. Gilman played for Navy as a freshman when the Midshipmen beat the Irish 28-27 in Jacksonville in 2016. He then transferred to Notre Dame, sitting out 2017 and playing last year in the Irish 44-22 victory in San Diego.

POLL IMPLICATIONS

Navy: The Midshipmen, who had climbed to No. 21 with five straight victories, could fall out of the AP Top 25.

Notre Dame: The Irish, who fell a spot to No. 16 despite beating Duke 38-7, could move up with one of their more complete games of the seaso