Serena Williams argues with the chair umpire during her match against Samantha Stosur. (Mike Segar/Reuters)

Battling back into contention for what would have been her fourth U.S. Open championship after a lackluster first set, Serena Williams was involved in yet another officiating controversy Sunday at Arthur Ashe Stadium.

Whether the sport’s biggest star was appropriately disciplined or unjustly penalized for shouting “Come on!” in the middle of a point will be debated from some time to come.

What was indisputable following Samantha Stosur’s resounding 6-2, 6-3 victory in the women’s final was that Williams’s penalty, which handed a service break to her opponent, didn’t decide the outcome.

Stosur, 27, was the superior player throughout the 73-minute rout, blasting more winners, committing fewer unforced errors, breaking Williams’s vaunted serve five times (four times, not counting the game decided by the penalty) and composing herself after the New York crowd, 23,000 strong, booed, hissed and heckled amid the disorder that brewed on court.

Although Stosur was the higher seed (ninth), few gave her much chance of defeating the 28th-seeded Williams, who was seeking her 14th major title and what would have been a record payday of $2.8 million.

Williams, 29, had been so dominant these last two weeks that it was easy to forget she had only returned to competition in June after being sidelined nearly a year by surgery and illness. Behind a tournament-high 52 aces, Williams stormed into Sunday’s final without losing a set, while Stosur struggled, forced to three sets in three of her six matches.

But on Sunday, Williams was a faint shadow of the champion who had steamrolled everyone in her path. Landing just 35 percent of her first serves, she was broken twice in the opening set. She was slow on her feet, sloppy with her strokes — committing 11 unforced errors to Stosur’s four — and oddly passive.

In 31 minutes, Stosur took the first set.

“I could feel my heart pounding out of my chest,” said Stosur, who had beaten Williams twice in six previous meetings.

Williams opened the second set in sluggish fashion, too. Facing break point, she blasted a forehand with such force it looked like a sure-fire winner.

“Come on!” Williams exulted over winning the point. The problem was that she screamed while the ball was in play.

Though Stosur barely nicked the ball with her racket, losing the point, chair umpire Eva Asderaki informed Williams that she had interfered with her opponent and, therefore, was being assessed a point penalty.

Williams didn’t understand and asked for an explanation, stepping toward the chair with her left hand on her hip.

It was the first hint of controversy, and the crowd booed at once — the tableau reminiscent of the 2009 U.S. Open semifinal in which Williams was called for a foot-fault at a critical juncture and unleashed a barrage of profanity at the lineswoman, shaking her racket in rage. Williams was defaulted from the match and hadn’t competed in the U.S. Open since. In fact, her probation for that outburst was still in effect Sunday, due to expire at the end of the match.

CBS’s on-court microphones picked up Williams’s reaction when Asderaki informed her of the point penalty.

“Are you the one who screwed me over last time?” Williams demanded of Asderaki. “Yeah, you are! Seriously, you have it out for me. That’s not cool. That’s totally not cool.”

Asked afterward if she had mistaken Asderaki with the chair umpire of two years ago, who was not the same person but also was blonde, Williams said: “I don’t know. Maybe. Probably for sure.”

Under the International Tennis Federation’s rulebook, Williams committed a “hindrance” violation in shouting during a point. Hindrance occurs, the rulebook states, “if a player is hindered in playing the point by a deliberate act of the opponent.” The penalty is one point.

The rulebook also states that if a player is hindered “by either an unintentional act” or an action “outside the player’s own control,” the point will be replayed.

Commentating on the match for CBS, Hall of Famer John McEnroe, legendary for his outbursts toward officials, argued that Williams’s ill-timed shout called for the point to be replayed.

Williams continued to rant about the penalty as the second set continued, berating the chair umpire.

“You’re out of control!” Williams said on the next changeover, via CBS microphones. “You’re a hater and unattractive inside.

. . . What a loser.”

Asderaki then gave Williams a code violation for verbal abuse. After reviewing the incident on tape and discussing it with Asderaki, tournament referee Brian Earley is expected to announce Monday whether the code violation warrants a fine and, if so, how much. Because Williams is also still on Grand Slam probation for her 2009 outburst, further penalties could follow.

In her postmatch news conference, Williams laughed when asked if she intentionally shouted to disrupt Stosur.

“No, I didn’t,” Williams said. “I think my opponent played really well. She did really good to even put her racket on [the ball]. I thought it was a clear winner.”

Notes: Americans Liezel Huber and Lisa Raymond defeated Vania King and Yaroslava Shvedova for the women’s doubles championship, 4-6, 7-6 (7-5), 7-6 (7-3). Grace Min, 17, of Duluth, Ga., upset top-seeded Caroline Garcia of France for the junior girls’ title, 7-5, 7-6 (7-3).