It looked like Konta's chances were disappearing fast but she battled back to make it 4-4 before her emotions boiled over.
Konta shook hands with her opponent, but bypassed Vieira Souza completely and stormed straight off the court, leaving Barty to fill the uncomfortable pause before the presentation ceremony by hitting a few balls into the crowd.
Konta, playing her first final of the year, found her rhythm in the second to take it to a decider, winning three games in a row after saving two break points in the seventh game.
Konta, who then had to serve to stay in the match, won only one more point as Barty clinched victory with a backhand pass.
British number four Katie Boulter had done well to reach a first WTA quarter-final but her Nottingham run came to an end on Friday as top seed Ashleigh Barty of Australia won 6-0, 6-2. You are making decisions that affect our lives. "Do you fully understand that?"
It was Barty's first tournament triumph of the year, the second of her career and a demonstration from the former junior Wimbledon champion that she could now even be an outside threat for the senior title at the Grand Slam. With only one able to move on to Sunday's title match, the key would be to who got the best jump in the opening games or the first to blink.
"I knew that Jo was going to be the toughest test this week, so I'm just really glad that I came through that and it was a really high quality match". Before she could return to court, rain fell on court for a time before the players returned to continue the match.
Britain's Johanna Konta won through to her first semifinal since Wimbledon previous year with a 6-4, 6-2 victory over Dalila Jakupovic in the WTA tour event in Nottingham-a warm-up for the lone grass-court Grand Slam.
Johanna Konta lost her cool during a defeat to Ash Barty in the final of the Nottingham Open and refused to shake hands with the chair umpire.