MELBOURNE (Reuters) - Serena Williams has a simple plan as she enters the twilight of her career.

One tournament at a time. Oh, and have some fun.

Serena Williams of the U.S. speaks during a news conference at the Australian Open tennis tournament in Melbourne, January 12, 2013. REUTERS/Navesh Chitrakar

The 31-year-old American, who is bidding for her sixth Australian Open title, enters the season-opening grand slam one of the raging hot favourites for the Daphne Akhurst Memorial Trophy arguably in the form of her life.

Williams compiled a 31-1 run from Wimbledon until the season-ending WTA Championships in Istanbul, winning the grass court grand slam, the Olympic gold medal and the U.S. Open as well as the Championships titles.

She continued that run by sealing the Brisbane title in her first tournament of 2013 and if successful at Melbourne Park, she will be just the French Open title away from completing her second 'Serena-slam' -- where she holds all four grand slam titles at the same time.

Despite her phenomenal run of form, and her superior match record against world number one Victoria Azarenka and number two Maria Sharapova, the powerful American was unsure if she would be able to complete a calendar grand slam.

"That's an incredible goal. It hasn't been done since the '80s," she said in reference to Steffi Graf's 1988 grand slam-winning season. "I don't know if I can do it. Maybe someone else can. We'll see."

Few would bet against the enigmatic Williams from achieving the result, given how well she was playing over the second half of 2012.

The real issue at Melbourne Park, however, is that she has from time to time run hot and cold.

Impressively destructive when the mood takes her, demolishing class opponents like the 6-0 6-1 thumping of Sharapova in the Olympics final and then, there are times when she is just not in the match.

LOVE PLAYING

Days when she loses to people she should ordinarily blast off court within an hour and then sit down to relax by watching television shows and movies on her computer.

Days like last year's 6-2 6-3 fourth round loss at Melbourne Park to then world number 56 Ekaterina Makarova.

As such, she has adapted a 'take it as comes' attitude.

"My goal is just to do the best I can," she added.

"Like I love playing. I want to be out there on centre court hopefully doing the best I can (and) I set my goals per tournament, go with it from there."

Williams, who has never been short in expressing opinions on her own abilities and is a raging hot favourite for her 16th grand slam singles title, tried to dampen down expectations before her first round clash with Romania's Edina Gallovits-Hall.

"I don't think like that," she replied when asked if she was a hot favourite for the title. "I feel like I have to win seven matches. Everyone in this draw has to win seven matches. They have the same opportunity to do it as I do.

"If I can do that, then that would be great. I think that's going to be the person that can win."

Williams has also entered the doubles with older sister Venus, something she said was now just for "fun", though the pair have accumulated 13 grand slam doubles titles and three Olympic gold medals.

"We love playing doubles. We'll definitely probably play most of the slams (but) we play it by ear. We just like to go out there and have fun and play.

"We don't have really big goals, now that I think about it. We just have fun."

(Editing by John O'Brien)

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