From the NYTimes:

Chamberlain could summon such heat when he needed it, but his greater reliance on a sinker helped induce contact and conserve pitches.

Chamberlain, who left for a pinch-hitter in the seventh, said he worked on the sinker with Chien-Ming Wang last spring, when both were coming back from injuries.

Chamberlain guessed that he threw 10 sinkers on Friday.

“It’s actually something I felt really comfortable with, obviously, from how many times I threw it tonight,” he said. “It gives me a different speed variation.”

I remember him toying  with it in Spring Training, but this articles says that he'd been playing with it longer than that.  I didn't honestly think he'd break it out this season.  For those of you keeping score at home, that's 5 pitches.  5 quality pitches.

It seems that Joba was giving Pf/x a lot of trouble.  

• He threw a pitch 90-93 with 6" of break, and Pf/x alternates between calling it a fastball and a change up.  I'm betting that's the sinker. 
• He regularly throws his curve in the mid-70s with 14" of break, but Pf/x mislabeled a few changeups (mid-80s, 10" break) as curves (2 in the third, 1 in the 5th).  Could these have been ridiculously slow and mobile sinkers?  It brings the count closer to the ten he mentions in the Times.
  
• His straight fastball came in 94-98 with 4" break.
  
• His longest AB of the night was a 9 pitcher affair with Kaz Matsui in which Joba threw 6 breaking balls.
  
• Joba recorded an out on 3 pitches or less for 11 of his 18 outs.  That is efficiency.