By Ian Browne / MLB.com

Scott Williamson tossed two hitless innings of relief and earned the win in Game 4. (Charles Krupa/AP)

Who is the closer? First it was a committee. Then it was Brandon Lyon. Then it was Byung-Hyun Kim. Then it was back to a committee. And now?

After all these months, the mystery might finally be solved. The last two days at Fenway Park, Scott Williamson has looked an awful lot like the closer of this team.

In large part because of Williamson, the Sox didn't have to close their season this weekend at Fenway Park.

The hard-throwing righty, acquired in a July 29 trade from the Reds, was the winning pitcher in Game 3 and Game 4 of the Division Series against the A's. A loss in either of those games, and the Sox were done.

Williamson wouldn't allow it, pitching a perfect 11th inning in Saturday's 3-1 win and then sending down six consecutive batters -- three via the strikeout -- in the 5-4 conquest Sunday.

"Today was beyond a doubt, the best he's thrown the ball (since joining the Sox)," said Boston catcher Jason Varitek. "It's confidence."

That confidence was often not there for Williamson over the last two months. His wife had complications following the delivery of the couple's first baby. Then Williamson's baby boy was hospitalized and had a spinal tap.

Only in the last couple of weeks have matters cleared up enough in his personal life for Williamson to fully sink his teeth into his role in the Boston bullpen.

Two weeks ago, Williamson called it "impossible" to have the majority of his focus on pitching.

Not anymore.

"It's a process. He's human being," said Sox GM Theo Epstein. "He comes over, his wife just had a baby and wasn't doing so well and then the baby wasn't doing so well. He battled through it, got his personal stuff settled down.

"Now, look where he is today from where he was a few weeks ago. He really wants the ball and feels comfortable. He's really toughened up and wanted to be the guy with the ball in the ninth inning."

Williamson's transition to Boston is finally complete.

"When you come over to a new team, the first thing you try to do is show these people and the fans what you can produce," said Williamson. "The flood gates kind of opened there for a while. I had one bad outing at Fenway, and I'm not used to being booed off the field."

By late Sunday afternoon, he came off the field to roaring approval from both the crowd and his teammates.

Kim fall-out: Kim's rude finger gesture to the crowd prior to Game 3 -- for which he later made a public apology -- was not the reason Sox manager Grady Little didn't use him in an 11-inning game Saturday night.

Though Kim was warming up in the late innings, he experienced tightness in his shoulder and it was relayed to Little from the bullpen that he couldn't pitch.

Little again chose to go with Williamson instead of Kim in Game 4. In fact, Kim never even warmed up.

It's unclear when Kim will be able to pitch again.

As for the finger gesture, Little and Epstein wouldn't say whether Kim would be fined by the team.

"We'll handle that within the organization," Little said. "It's not the first time something like that has happened and it probably won't be the last. I'm sure it's something he's disappointed about doing. I know we are. We can't turn back the clock. "

"I've already talked to him about it," said Epstein, who chose not to elaborate any further.

Pedro Martinez   /   P
	Height: 5'11" Weight: 170 Bats/Throws: R/R More info: Player page Stats Splits Red Sox site

Pedro stays with team: Though Pedro Martinez certainly had the option of flying ahead to Oakland for Game 5 on Monday, the ace chose to stay with his team for Game 4.

Martinez warmed up in the bullpen in the eighth inning in Game 3, and would have pitched in a save situation if the Sox had taken the lead going into the ninth.

It never materialized. Martinez told Little on his way out the door Saturday night that he was available for action in Game 4. The manager chose not to take him up on the offer.

"I can't see myself doing that," said Little. "Pedro Martinez left here last night and said he was available again today. I can't see that happening."

It didn't, and now Martinez is fully fresh for Game 5.

David Ortiz   /   DH
	Height: 6'4" Weight: 230 Bats/Throws: L/L More info: Player page Stats Splits Hit chart Red Sox site

Ortiz sore, but good to go: There was a slight possibility David Ortiz was going to be out of the lineup for Game 4 because of some pain in his right knee caused when he slid into second base during one of the games in Oakland. But Ortiz tested it out during batting practice, and was good to go.

That turned out to be a good thing, as Ortiz's two-run double in the bottom of the eighth was the game-winner Sunday afternoon.

As for that knee?

"It doesn't really affect his running speed," quipped Little of the slow-footed Ortiz.

Cloninger throws a strike: In a classy gesture by the Red Sox, pitching coach Tony Cloninger threw out the first pitch before Game 4.

Cloninger was diagnosed with bladder cancer during Spring Training and has been on medical leave most of the season. He's been in uniform during this series, helping interim pitching coach Dave Wallace. Because of Major League Baseball rules, Cloninger has not been permitted to sit in the dugout during the games.

Flying high: Despite the fact the Sox entered Game 4 trailing in the series, Little felt prior to the game that all the pressure had shifted to the A's.

"You have one clubhouse over there dreading a flight back to Oakland and we're looking forward to it," Little said before the game.

If the A's had beaten the Sox in Game 4, they could have hopped a short flight to New York for the beginning of the American League Championship Series.

Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.