Mike Singletary became so frustrated with his team’s poor play he couldn’t help himself but to verbally respond to former 49er Harvey Dahl when the offensive lineman engaged the coach near the San Francisco sideline with Atlanta driving downfield again.

Roddy White had a 90-yard catch-and-run for a touchdown and a 31-yard TD reception, Michael Turner ran for three scores and the Falcons flattened the 49ers 45-10 on Sunday to end San Francisco’s five-game home winning streak.

"I’ll put it this way: I wish I had more coaching etiquette," Singletary said afterward. "I don’t. I love my players and when someone responds about my players in a particular way, I may do some things I shouldn’t do. I have to get better at those things as time goes on. ...

"Even though the player was talking to me, I should not have said what I said. It wasn’t anything bad, it was just something that shouldn’t have happened."

Of their third-quarter spat, Dahl would only say, "He’s a fiery guy."

White finished with eight catches for a career-high and franchise-record 210 yards against the 49ers’ typically stingy defense. Six of those receptions were in the first half for 185 yards as Atlanta (3-1) came out of its bye week sharp and finished the day with a 477-279 advantage in total yards. Matt Ryan completed 22 of 32 passes for 329 yards and two TDs and also ran for a late score.

San Francisco (3-2) flopped in its biggest test yet, falling to its worst defeat since a 41-0 loss at Kansas City on Oct. 1, 2006, under former coach Mike Nolan. Singletary said his players weren’t prepared.

"We lost our composure," linebacker Manny Lawson said.

It got quiet in a hurry at Candlestick Park on a gray October afternoon — and the Niners were booed off the field at halftime trailing 35-10. Fans left in droves in the fourth quarter.

The 49ers failed to respond even after Singletary called timeout midway through the first quarter and brought his team together for a spirited pep talk. White scored his first touchdown on the very next play, and his big day helped Atlanta to its first road win of 2009.

On his 90-yard TD, White somersaulted into the end zone, a flip that landed him an unsportsmanlike conduct penalty.

"He didn’t hit the landing because if he hits the landing it’s not a 15-yard penalty," coach Mike Smith joked. "I told him if he’s going to do it, it needs to be Olga Korbut. And he looked at me like he doesn’t know who Olga Korbut is. Then I told him, ‘Well, maybe Mary Lou Retton.’ And then I figure that’s ‘86, he doesn’t know who Mary Lou Retton is. It went right over his head and my head."

White broke the previous franchise mark of 198 yards receiving set by Terance Mathis against New Orleans on Dec. 13, 1998.

"I felt like I haven’t been playing well up to this point in the season," White said. "Me and coach Smith had a talk. He was like, ‘You gotta get back to being yourself again. You gotta go out there and be the old Roddy. No pressure. Just go out there and play."’

San Francisco’s three turnovers were one more than the team had in its first four games combined. After White’s second touchdown in the first half, Delanie Walker fumbled the ensuing kickoff and the Falcons recovered. It looked as if the ground might have caused the fumble, but San Francisco was out of timeouts and couldn’t challenge the play.

Even when things went right for the 49ers, they ended up wrong.

Dre’ Bly intercepted a pass by Ryan at the San Francisco 10 midway through the third quarter but was caught from behind when it appeared Bly began celebrating during his return. Ryan swiped at the loose ball on the ground before center Todd McClure fell on it for the Falcons.

"Dre’s going to be Dre’," Bly said. "When I make plays, and I’ve made a lot, I express myself."

Shaun Hill struggled mightily, and so did the entire San Francisco offense. Hill’s perfect 7-0 record at home as a starter evaporated. The 49ers clearly miss star running back Frank Gore, out until after the bye with a sprained ankle.

Hill completed only four of his first 15 passes and finished the day 15 for 38 for 198 yards and three sacks.

San Francisco lost strong safety Michael Lewis to his third concussion of the season. He went down early in the third quarter after leading with his helmet trying to tackle Turner. Lewis sustained two concussions during an 11-day span in the preseason.