Konta looked set to test the American following her superb run on form but the British number one was outclassed on Rod Laver Arena and beaten 6-2 6-3.
It is a mark of how far Konta has come that she agonised over the defeat, given the Briton was playing only her second grand slam quarter-final while her opponent was into her 47th.
Williams goes through to meet Croatia’s surprise semi-finalist Mirjana Lucic-Baroni.
“I was crying, so I’m a bit blocked up. I cry too,” Konta said.
“I cried because I’m generally quite an emotional person. I think I’ve never hid that away.
“I’ve worked incredibly hard to direct that emotion into a positive way and into a constructive way on court but off court I’m still very emotional.”
Konta held her own in stages but once gaining the momentum, too quickly handed it back.
She failed to break early in the first set, when Williams grew agitated at her misfiring serve, and then did in the second to lead 3-1 but never won a game thereafter.
After the match, Williams paid tribute to her opponent by dubbing her a future Australian Open champion.
“That’s nice, I will do my best,” Konta said later. “I think it was probably one of the best experiences of my life.
“I think there’s so many things I can learn from that, so many things I can look to improve on, also acknowledge some things that I did well.
“I think, credit to her, she played an almost perfect first set. I felt she really did incredibly well. She just showed why she is who she is.”
Williams’ first serve was not prolific but lethal, with Konta able only to win three of the 26 points when it found its target.
Konta’s game also seemed well-suited to Williams, who can struggle against more crafty opponents but seemed to enjoy her powerful baseline hitting.
“I definitely would have liked to have had a bit more say in the match than I did,” Konta said.
“But unfortunately that’s also so much to do with Serena herself, the kind of tennis that she plays.
“I don’t think there’s one player on tour that goes up against her and feels like they’ve got much of a say in the matches.”
Konta said she also found it difficult to relax.
“I probably just wanted to do really well,” Konta said. “So I think I may have put a little too much expectation and pressure on myself, and not given enough credit to the situation.”
Williams’ hopes of sealing an Open era 23rd grand slam title, and her seventh at Melbourne Park, remain very much intact while a ninth major final meeting with her sister Venus is also a possibility.
The most prestigious siblings in tennis show no sign of fading, this the first time in the Open era that two players aged 35 or older have reached the last four at the same grand slam.
Venus plays fellow American Coco Vandeweghe in the other semi-final.
On Konta, Serena said: “I feel like she’s a great all-around player. So I feel like I had to be on it all around today.
“She’s a player that I actually watch a lot. I don’t know, they play her a lot on the TV.
“I didn’t realise she was so tall, to be honest. I thought she was more my height. But I think she’s taller than me.
“Other than that, I’ve always wanted to play her. So it was a good opportunity to go out there.”