MELBOURNE, Australia (AP) -- Serena Williams stuck out a fist in mock triumph and mouthed ''C'mon,'' careful not to push her point too far.

The 33-year-old Williams was closing in on her 19th Grand Slam singles title, her 16th straight win over Maria Sharapova and her sixth Australian Open championship when she was docked a point by the chair umpire for hindrance - for yelling in celebration too early when she thought she'd hit a service winner.

She didn't let that, or another early celebration on match point, or a hacking cough that made her sick, become distractions. Instead, Williams maintained her composure to beat Sharapova 6-3, 7-6 (5) on Saturday night to continue her 100 percent record in finals at Melbourne Park and move closer to Steffi Graf's record of 22 major titles in the Open era.

''I got too excited and I hit a great serve ... I didn't expect her to get it back,'' Williams explained of the hindrance call in the seventh game of the second set. ''I said, `C'mon', a little too soon. I guess there's a rule that you can't do it. So I'm fine with it. I moved on very fast to the next point; just tried to stay as focused as I could.''

The muted fist pump, she said, was just for fun.

''I'm like, `C'mon.' It just goes to show you I have more fun on the court. I would have never done that three years ago, four years ago,'' said Williams, who has let similar calls upset her in the past. ''So I just kind of made a little sarcasm after that.''

On her third match point, she let her racket go before hearing a let call to what she thought was an ace.

''I thought, Wow this is it, I did it,' only to hear let. I was like,OK Serena!''' she said.

So she fell back on her biggest weapon, firing another ace - her 15th of the set and 18th of the match. This time, after checking it was official, she bounced around like a little child and the celebration was real.

''I'm so honored to be here and to hold this 19th trophy,'' Williams said. ''I didn't think it would happen this fast, to be honest, but it feels really good.''

Williams, at 33 years and 127 days, became the oldest winner of the Australian women's title in the Open era and moved into outright second place on the list of major winners in the Open era, moving clear of Chris Evert and Martina Navratilova on 18.

No. 20 is her next objective, and her next chance is at the French Open.

''When I think about Paris, I don't think about 20. I just think about winning there,'' said Williams, who didn't reach a quarterfinal in a Grand Slam between her wins at the 2013 and 2014 U.S. Opens.

Still affected by a recent cold, Williams controlled the first set around a rain delay when play was stopped for 13 minutes during the sixth game for the roof on Rod Laver Arena to be closed. Williams came back on court momentarily, but returned to the locker room.

''I had a really bad cough, I ended up throwing up,'' Williams said. ''I think in a way that just helped me - I felt better after that.''

She returned to court and fired an ace to start a run of six straight points to take the set away from Sharapova.

Williams won the first six points of the second set, too, before Sharapova started hitting out.

The five-time major winner had 18 of her 21 winners in the second set, and fended off four break points.

No. 2-ranked Sharapova saved two match points, including one in the 10th game when she hit a forehand winner down the line, and she calmly held serve twice to stay in the match. In the end, though, it wasn't enough to end a decade-long losing streak to Williams.

''I haven't beaten her in a long time but I love every time I step on the court with her,'' said Sharapova, who trails 17-2 in career head-to-heads against Williams and hasn't beaten the American since 2004. ''I've had some of the best memories of my career on this court and also some of my toughest losses, but that's the life of a tennis player.''

On the men's side, Fabio Fognini and Simone Bolelli became the first all-Italian team to capture a Grand Slam men's doubles title in more than 50 years after beating French pair Nicolas Mahut and Pierre-Hugues Herbert 6-4, 6-4.

Novak Djokovic has won all four times he's reached the Australian Open final and is aiming to maintain his 100 percent record when he takes on Andy Murray in Sunday's singles final.