Give Serena Williams the Australian Open trophy now, because beaten semi-finalist Agnieszka Radwanska says no one can beat her.

Not if Williams maintains the form she reached on Thursday in swatting aside the world No.4 in straight sets.

"I don't think anyone can really play on that kind of level at all," Radwanska said.

"If she's playing her game, it's different level.

"She goes on court and she just wants to kill it. Going like full power for everything.

"When you serve 190 (km/h) wide, I don't know who's going to take that. Definitely not me."

After 64 minutes, Williams won her way into a seventh Australian Open final with a 6-0 6-4 victory.

The brutality of Williams' first set took even Melbourne Park veterans by surprise.

The American hit 18 winners in the bagel, all won without a single deuce.

Williams wasn't playing a nobody.

This was against the fourth seed, who came into the Australian Open with four titles since Williams last played a match.

The Pole claimed the WTA Finals and another three tournaments in Williams' four-month sabbatical between the US Open and the Australian Open.

But she was powerless to stop Williams in her relentless run to a 22nd major title.

Radwanska agreed that Williams' first set was as close to tennis perfection as she had ever seen.

"There was just no mistake," she said.

"Unbelievable serve. Everything, she was going for it.

"I couldn't do much. Not at all, actually."

Radwanska, set to improve her ranking to world No.3 after a run to the last four, said she would be grabbing the popcorn on Saturday night in anticipation of a great show.

"I'm not even angry because I know she was just playing too good today," she said.

"I'm just going to watch the final."