The Yankees dropped their magic number for clinching the AL East to three Friday night by beating the Red Sox soundly 9-5. Alex Rodriguez had a big night, going 3-for-3 with a two-run homer, four RBIs, and three stolen bases, but the story of the game was the respective highs and lows experienced by the opposing starting pitchers.

Jon Lester gave up a single to Derek Jeter on his first pitch of the game, and though he ultimately allowed only Jeter to score (following a stolen base on an Alex Rodriguez single), he needed 30 pitches to get through the inning. After stranding two runners in the second, including his second walk in as many innings, Lester got into big trouble in the third.

Mark Teixeira led off the third by concluding an eight-pitch at-bat with a single to left. Rodriguez then crushed an inside pitch into the second deck in left field (just the second time a fair ball has reached that level, both of them hit by Rodriguez). The Yankees then loaded the bases on a single by Hideki Matsui, a Robinson Cano double, and Lester’s third walk. With the bags juiced and one out, Melky Cabrera lined a 1-0 pitch off the inside of Lester’s right knee, plating Matsui and knocking Lester out of the game with what ultimately proved to be just a bad bruise. Hunter Jones replaced the injured Lester and allowed Cano to score before ending the inning with the Red Sox trailing 5-0.

Meanwhile, Joba Chamberlain, who suffered what seemed like a significant performance setback against the punchless Mariners in his last start, retired the first 11 men he faced before Victor Martinez deposited a high fastball in the Yankee bullpen in the top of the fourth. That solo homer came on what was just the 44th pitch of the night from Chamberlain. After stranding a subsequent single by Kevin Youkilis, Joba got into immediate trouble in the top of the fifth when a leadoff single by Jason Bay and a J.D. Drew double put men on second and third with no outs.

It took Joba just seven pitches to work out of that jam. Jason Varitek popped out on the first pitch he saw. Alex Gonzalez struck out on four, and Jacoby Ellsbury grounded to Mark Teixeira on a 1-0 count. Teixeira took Ellsbury’s ball to the bag himself, but Joba was running over to cover just in case and simply turned right and ran right into the dugout as Tex made the play.

A walk to Dustin Pedroia to start the sixth and a two-out two-run homer to lefty by David Ortiz soured his final inning, but overall the night was a huge success for Chamberlain, who had been showing progress in his two starts prior to his disappointing outing in Seattle. Though his recent innings limits were partially to blame, the game marked the first time Chamberlain had completed six innings since August 11, his first win since August 6, and his first quality start since he dominated the Rays on July 29.

Joba will make one more regular season start, on Wednesday against the Royals. The Royals aren’t much to contend with, but neither were the Mariners. Joba had a 90-pitch limit Friday night and used just 86 of them in six frames. He has thrown 152 2/3 innings on the season, but should be allowed to pitch without limits against the Royals in preparation for potential playoff work. His performance in that game could determine a lot, including which ALDS schedule the Yankees choose. If he’s similarly effective, the Yankees might prefer to let Joba start an ALDS game in order to keep him in the groove.

Meanwhile, the Yankees stole seven bases against Jason Varitek in this game, providing a preview of how they might play against the Sox in a potential ALCS matchup. Varitek has thrown out just 15 men all year, a mere 14 percent of attempting basestealers. Victor Martinez has been equally inept at catching thieves, throwing out just nine men for an identical 14 percent caught-stealing rate. The Yankees, meanwhile, have four starters in double digits in steals (Jeter, Rodriguez, Damon, and their center fielder, be it Cabrera or Gardner), and Robinson Cano contributed with a steal of second Friday night. Mix in a postseason roster that could include Freddy Guzman and the Yankees could give the Red Sox fits on the bases, turning singles and walks into doubles with regularity, rendering irrelevant Joe Girardi and Derek Jeter’s irritating fondness for the bunt. Keep an eye on those Yankee baserunners over the final two games of this series.

Finally, last night’s game was the last of the 2009 season to be broadcast on “My9.” The WWOR game broadcast is simply the YES telecast with a different station ID, but the lack of a full postgame treatment and the deplorable duo of veteran anchor Russ Salzberg and reporter Scott Stanford have been regular irritants for me all season.

Back in the ’80s, I used to bemoan the increasing number of games given to cable as opposed to broadcast, despite my having access to both, but I realize in retrospect that most of my harping had to do with the fact that Phil Rizzuto only worked the WPIX games. The Yankees have bounced around the old dial since Scooter’s retirement, and the patronizingly nicknamed “My9” has been their worst stop by far.

Salzberg’s raspy shout makes Michael Kay sound like Barry White, while Stanford has the reportorial skills of a high school freshman and screen presence that suggests he won the job in a contest last week (curiously, he’s better as an anchor, and not just better than Salzberg, proving he’s miscast in his current role). Much like the dismal state of the Yankees radio broadcast, the My9 post-game serves largely to highlight the high quality of the YES broadcast itself. I’m not daft enough to suggest that’s by design, but it does make a regular viewer such as myself thankful that such annoyances are relegated to the fringes. I sometimes worry that overexposure to Michael Kay is rotting my brain, but I’ll take Kay over Salzberg and company any day and twice on Tuesdays. Of course, now that we’ve shed My9, we run the risk of having to watch crucial games on FOX. Sigh.