Radwanska looked like she would sneak it out in straight sets, getting within six points of winning serving at 7-5, 4-4 and 30-15, but she wouldn't win another game - Niculescu reeled off eight games in a row from there, completely running away with it in a 27-minute third set to close it out, 5-7, 6-4, 6-0.
"The goal is always to win, but she was just playing very good tennis - very solid with no mistakes," Radwanska said. "She was playing with very good touch and very good timing. She was doing it great.
"But having four matches here is great preparation for me, and I'll just try to keep improving."
Meanwhile on the other half of the draw a WTA Rising Star was truly rising up - 17-year-old Ana Konjuh not only won her rain-delayed quarterfinal match against American qualifier Sachia Vickery, 6-2, 6-2, but she also won her semifinal encounter against No.5-seeded grass court lover Alison Riske, 6-4, 6-3.
Riske was very impressed, indeed. "She's already an amazing player, but that girl's got some big game," the American said. "I was very impressed. People will be hearing a lot about her in the future."
"I didn't start well this year, and I've kind of been in a bad mood the last few months, and I came here with nothing to expect," Konjuh said. "Now I'm in the finals, so it's a really exciting result for me."
Niculescu and Konjuh will be playing each other for the first time in a Monday final.
"She's a really good player with a lot of years on tour right now, and she knows the game well," Konjuh said. "I hope I can recover now and play as well as I have the last few days in the final tomorrow."
The doubles title went to No.1 seeds Raquel Kops-Jones and Abigail Spears, who rallied from 7-4 down in the match tie-break to beat British pair Jocelyn Rae and Anna Smith in the final, 3-6, 6-3, 11-9.
"It was tough conditions for everybody with the rain delays, but we wanted to go out there and have fun," Spears said. "Our goal is to enjoy our tennis and making good shots, and that's what we did."
"We had a rough French Open," Kops-Jones commented. "To start off on the grass with a win like this is exciting. We played well all week and we're just excited to keep going in the grass court season."
too good from my opponent 2day but very thankful 4 a fun first week on the beloved grass???will miss @Tropeiro_Brazil !Thank u 4 everything?