Konta, 26, was bidding to become the first British woman to reach a Wimbledon singles final in 40 years today.
But she met her match in five-time SW19 champion Williams who put on a Centre Court semi-final masterclass.
Williams may be 37 but she showed age is just a number as she handed out a Wimbledon lesson to win 6-4 6-2 in 1hr 13mins.
Victory ensured she became the oldest player to reach a Grand Slam semi-final since Martina Navratilova at Wimbledon in 1994. Garbine Muguruza awaits in the final on Saturday.
Konta had two break points at 4-4 in the first set but the elder of the Williams sisters snuffed out the pair of them. She then broke the very next game before blitzing through the second set.
Williams said: “I’ve played a lot of finals here. I couldn’t have asked for more. Well, one more win will be amazing. It’s not a given but I’ll give it my all.
“I thought the crowd were very nice to me. I know they love Jo, she gave it her all. There’s a lot of pressure but she handled it well. I felt my experience helped a lot.
“She played so well. At no point was it easy. I tried to climb on top each time to win another point and wow it was done. I’m so happy.”
Victory on Saturday will put Serena within one Wimbledon win of her little sister’s seven titles.
On Serena, who misses this tournament as she’s due to give birth in September, Venus said: “I miss her terribly, I miss her so much, I wish she was here.
“I’m going to have to ask Serena for some pointers. Normally it’s her in these finals.
“I just wish she was here. I wish she could do it for me but now I have to.”
Virginia Wade, the last Brit to win the women’s title at SW19, praised Konta for her Wimbledon showing despite it ending in hearatche.
She said: “I thought Jo played really well. Every time she had a little bit of an edge Venus came up with something better.
“We’ve been watching Jo beating everybody by taking the ball early and pounding it but it was actually Venus who was absorbing the pace and hitting harder.
“Frankly, I think Venus has been playing very well this year. I said to Billie Jean that maybe Serena has given Venus tips on her serve but she said no, she’s been out there!”
Tennis legend Navratiolva pin-pointed a clutch point in the first set as the turning point.
Venus was down a break point at 4-4 when she came up with a hammer second serve that clipped the line. The American went on to hold and didn’t look back.
Navratilova said: “The match very much turned at that break point, at 4-4 that break point.
“Venus Williams, second serve, goes for broke, hits the serve and she never looked back after that point.
“It almost relaxed her and she broke very next game. She run away with it in the second set, too solid.”
