Both happened when Weir birdied the second extra hole to defeat Howell in the Nissan Open at Riviera Country Club.
Weir laid up on the 315-yard, par-4 10th, the second hole of sudden death, while Howell tried to drive the green.
The strategy worked in Weirs favor, as he was left with a scant 76 yards from the fairway. Howell was in the right greenside bunker, faced with a lengthy sand shot and little green to work with.
Howell played a brilliant approach to six feet. But after Weir made his eight-footer for birdie, Howell pulled his effort to tie.
Following a year when he didnt even post a top-10 finish, Weir collected his second victory of the season, having also captured the Bob Hope Chrysler Classic.
Getting ready for this year, I got away from the game for a couple of months and just needed to reassess my passion for the game and why I was playing, he said. I came to a few conclusions that motivated me this year to work hard in the off-season ' but I never expected to play this well.
Weir shot 5-under 66 to finish regulation at 9-under-par 275, and was surprised to find himself in a playoff after Howell shot 73.
I just wanted to play solid and try to shoot a really good number. I wont say winning was in my mind, said Weir, who collected $810,000 and moved into first place on the seasonal money list with just over $2 million.
The defeat was a near shock to Howell.
At no point did I think I wasnt going to win the tournament, he admitted.
When asked to comment on the loss, the normally docile 23-year-old said as politely as he could, It sucks.
This is Howells second playoff defeat. He lost to Shigeki Maruyama in the 2001 Greater Milwaukee Open.
In Milwaukee, I was much more nervous, Howell said. I felt a lot more calm this one than in Milwaukee.
Weirs second win was similar to his first. He overcame a four-shot deficit on Sunday, making a birdie to win after laying up with his approach on a par-5, while Haas went for the green in two and found the water.
The cautious approach worked again this time. He said he had tried to drive the 10th green each of the first three days, and played the hole in 1-over. He laid up in regulation Sunday and made birdie. He did it again in the playoff to the same result.
Weir has now won five times on tour ' all of which have been come-from-behind victories.
I guess Im not sure why that is. I guess I can go out there and freewheel it, he said. Just a little more peaceful mindset starting the day.
Howell said he was a peace despite sleeping on the 54-hole lead for the first time as a professional. He started the day three shots clear of his nearest opponent, Nick Price.
Howell even birdied the par-5 first, but Price made eagle. There you have it. I make birdie and lose a shot. This game can change so fast, Howell said.
While Price continued his West Coast drought, Tiger Woods extended his losing streak as a professional in this event to six. He shot 6-under 65, his lowest round of the week by three strokes, to move from tied for 28th place as the day began into a tie for fifth with K.J. Choi (72).
Weir was in need of a Tiger-like round to have any chance of overtaking Howell. He birdied his first two holes on the back nine to get to 4-under for the day, and 8-under for the tournament.
Yet, he still found himself trailing Howell by three strokes.
Howell turned in even-par 35 to remain at 11-under. He stayed there after trading a bogey at 10 ' he hooked his tee shot 50 yards left of the pin while going for the green ' for a birdie at 11.
At the par-4 12th, he drove the ball into the ideal portion of the fairway. Faced with 180 yards to the pin, he came up short on his approach. The ball landed in the right greenside bunker, from where he wasnt able to advance his ball onto the green. He made bogey to cut his lead to two.
Another bogey ensued at the 176-yard, par-3 14th. Howell had an 8-iron into the green, but left it 65 feet right of the pin. He three-putted from there to fall to 9-under, tied for the lead with Price and Weir.
Price didnt stay there long. He missed the green at 15 and 16, and bogeyed them both. He shot 72 to tie first-round leader Fred Funk (68) for third.
I just didnt feel very comfortable out there, said Price, who added that he tried to work out the kinks in his swing in a late practice session Saturday. I ought to be happy where I finished in one respect, but Im disappointed because Im more capable of hitting the ball a lot better than I did.
That left Weir as Howells only foe. The left-handed Canadian played near perfect golf coming home. After his birdie-birdie start to the back, he saved par from eight feet at both 12 and 13.
He birdied 17 and parred 18 before heading to the practice range to stay loose.
Howell could have avoided sudden death if he could have matched Weirs finish. But he wasnt able to get up and down for birdie at the par-5 penultimate hole and two-putted the last.
The two went back to the 18th hole. They each made par, with Weirs winning effort dying on the lip.