SAN FRANCISCO — The San Francisco 49ers' leader knows he lost his cool.

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, yesterday 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. ... I should not have said what I said."

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.

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," Atlanta coach Mike Smith joked. "I told him if he's going to do it, it needs to be Olga Korbut."