Big win, bigger loss; Brady injured; Patriots persevere.

Byline: Jennifer Toland

FOXBORO - Tom Brady made his 128th straight start yesterday, but by midway through the first quarter, he was finished.

The opening day crowd at Gillette Stadium held a collective gasp as Brady limped off the field and down to the locker room, never to return.

"When you lose a player, it's bad," linebacker Adalius Thomas said, "but you have to go on. The game's not going to stop."

The Patriots' offense rallied around backup Matt Cassel, the defense made a key red-zone stop late, and New England held off the Chiefs, 17-10, for its 20th consecutive regular-season victory.

"It's always good to win on opening day," Patriots coach Bill Belichick said.

But the possibility of losing Brady looms.

The Patriots announced Brady had a left knee injury. As he grimaced on the ground after taking the hit from Kansas City safety Bernard Pollard, he was grabbing his lower leg, below the knee. Last night, multiple Internet sites were reporting Brady tore his anterior cruciate ligament and likely was out for the season.

"I don't know his injury or what happened," wide receiver Randy Moss said, "but all I know is he didn't come back."

Pollard rolled into Brady as he let off a 28-yard completion to Moss (which Moss fumbled away).

Patriots running back Sammy Morris, who was blocking Pollard on the play, said his initial reaction was that Pollard delivered a low hit on Brady.

"I have to look at film to see exactly what happened," Morris said, "but yeah, that's what I thought initially."

Pollard said the play was not intentional.

Brady did not play in the preseason because of a right foot injury. Cassel started all four exhibition games and did not lead a touchdown drive. His future in New England seemed in question, but he made the team as Brady's No. 2, the Patriots axing Matt Gutierrez instead.

Cassel watched with little concern when Brady was down yesterday.

"I've been here for four years, and every time he's been knocked down, he's gotten right back up," Cassel said. "I was just anticipating that being the next move."

Instead, Cassel took over on the Patriots' next possession - at their own 2-yard line.

In the huddle, talk was positive.

"C'mon, Cassel, let's get it started!" running back Laurence Maroney said.

Backed up at the 1 after Morris lost a yard on first down and was stopped for no gain on second, Cassel's first pass of the game, a 51-yard completion to Moss, gave the Patriots some breathing room and Cassel some confidence.

"We had a few handoffs in there, and you start to just say, `Look, I'm going to be playing here,'" Cassel said. "You just take a deep breath and get going. After that pass, though, it definitely calmed the nerves down a little bit, and I said, `I can do this' and `Let's roll.'"

Cassel completed the 98-yard drive with a 10-yard TD pass to Moss. It was Cassel's third career touchdown pass.

Cassel finished 13 of 18 for 152 yards. He was sacked twice.

"I think he's taken a lot of fire, especially in this preseason," left tackle Matt Light said. "I felt like his job as a backup quarterback is to understand everything we do on offense and be able to step in there and perform at a high level. That's what's expected of him, and that's what he did."

Cassel got a lift from his running backs, who combined for 126 yards and a 4.5-yard average. Morris led the way with 10 carries for 53 yards and a touchdown.

"I thought Cassel played an outstanding game," Maroney said. "He came in, stepped up and took control of the team."

Chiefs starting quarterback Brodie Croyle was 11 of 19 for 88 yards before departing with a shoulder injury, suffered when he was sacked by Thomas in the third quarter.

Damon Huard took over, and with New England clinging to a touchdown lead, the former Patriots backup completed a 68-yard pass to Devard Darling. Newly signed cornerback Deltha O'Neal chased Darling down and tackled him at the Pats' 5-yard line with 53 seconds to play.

The Patriots kept the Chiefs out of the end zone as Richard Seymour and Mike Vrabel combined to stuff running back Larry Johnson, and Huard threw three incomplete passes.

"Praise to the whole defense," said cornerback Ellis Hobbs, who had an interception, sack and 51-yard kickoff return. "You saw everybody doing their job. Even in practice, when you're put in those situations in the red zone, you tell yourself, `It's not going to be on me. It's not going to be on me.' When you have that mentality, and all 11 guys have that mentality, you're going to have some positive days."

The Patriots' starting defense gave up long scoring drives to begin each preseason game. Kansas City sustained a 13-play, 51-yard drive that ended with a Nick Novak 40-yard field goal just before halftime. The Chiefs were 8 of 16 on third down.

The Patriots held Johnson in check. He carried 22 times for 74 yards, a 3.4-yard average.

NAME: NEW ENGLAND PATRIIOTS

ART: PHOTOS

CUTLINE: (1) Patriots quarterback Tom Brady is helped off the field in the first quarter after having his left leg buckled by Chiefs safety Bernard Pollard. Brady was replaced by ... (2) ... backup Matt Cassel, who had reason to celebrate after throwing a touchdown pass to Randy Moss in the second quarter.

PHOTOG: ASSOCIATED PRESS PHOTOS