San Francisco • Colin Kaepernick rarely utters anything pointed or emotionally charged.
He offered a clear message to Clay Matthews and the Packers' defense after delivering Green Bay another beating: "If intimidation is your game plan, I hope you have a better one."
Kaepernick took a late, out-of-bounds hit from Matthews in the second quarter and showed no signs of slowing down, throwing for a career-high 412 yards and three touchdowns, with 13 completions to Anquan Boldin in San Francisco's season-opening 34-28 victory Sunday.
Boldin's sensational San Francisco debut helped keep his team on quite a roll in what has evolved into a fierce NFC rivalry. And Vernon Davis did his part in a prolific passing game led by Kaepernick.
From Super Bowl champion Baltimore to contender again with another coach named Harbaugh, Boldin was unstoppable. He finished with 208 yards receiving and a 10-yard touchdown.
Davis made a pair of TD catches for the NFC champion Niners.
Boldin sure showed he is a reliable replacement for injured Michael Crabtree.
"We knew they were going to come in ready to play after what happened in the playoffs," Boldin said. "We had to come out and match their intensity."
Frank Gore scored a go-ahead, 1-yard touchdown with 5:47 remaining as the 49ers made it three straight against Aaron Rodgers and Co., after beating Green Bay last September to open the season and then 45-31 in the NFC divisional playoffs.
Boldin sure has a knack for season openers, coming through with 10 catches for 217 yards in his first career game with Arizona, seven catches for 110 yards in his first game for the Ravens in 2010 then this superb outing.
Kaepernick marched his team 80 yards on five plays to take the lead. The 49ers answered after Packers rookie Eddie Lacy put Green Bay ahead on a 2-yard run.
Rodgers threw for 333 yards and three touchdowns, but the Packers departed from Candlestick Park with another defeat eight months after that embarrassing postseason game.
Boldin came back from an apparent twisted right knee early in the fourth quarter to make a 43-yard catch in the decisive drive. He also converted on fourth down with a 15-yard catch that set up Phil Dawson's late 33-yard field goal.
The Packers promised to target Kaepernick, but they probably meant for it to be in bounds. It wasn't.
"First off, it wasn't a very smart play," he said. "I'd already committed to hitting the quarterback. I guess I should've figured he was going to step out of bounds. But it's nothing personal. I went up to him later and was joking around with him."
"The late hit certainly was," coach Jim Harbaugh said.
Matthews put the hit on Kaepernick, and 49ers left tackle Joe Staley made contact with Matthews after the play, receiving an unsportsmanlike conduct penalty. Both teams scuffled, and the officials mistakenly replayed the down.
"I'll try to do a better job just keeping my cool," Staley said. "I didn't want see Kaep get nailed like he did out of bounds. That's our guy out there. I'll protect anybody. Anything I feel like is outside the rules ... some of it was the comments he made this week about going after the quarterback. I wanted to grab him and let him know that's not going to fly. That's all I did."
San Francisco took the lead on that play when Kaepernick found Boldin for a 10-yard touchdown. Had it been fourth down, the Niners might have tried a field goal.
"The down should have counted," referee Bill Leavy said after the game. "The penalties were both dead ball, and they should have offset at the spot where the runner went out of bounds. And it would have been fourth down."
Monday night football
P Philadelphia at Washington, 4:55 p.m., ESPN
• Houston at San Diego, 8:15 p.m., ESPN