An excellent first-team best score of 91 from youngster Will Bennison was the cornerstone of Yorkshire’s 273-9, but it maybe should have been more as they lost momentum in mid-innings.
And, ultimately, it did not prove quite enough as in-form South African Verreynne came in to help Notts from their stuttering start with 105 off 123 balls.
After he was out, Haynes carried on the fine work as the former Worcestershire man got his side over the line with only his third List A century.
His former Pears team-mate Dillon Pennington, who had earlier struck four times with the ball, assisted at the end with two fours and a six in his 18-ball cameo of 22.
Earlier, after starting with the wickets of Freddie McCann and visiting skipper Haseeb Hameed, Coad claimed a fine 5-52 – but how different it might have been if Verreynne had not survived the hat-trick ball.
Notts, who last won a List A trophy at Lord’s in 2017, now have a chance to follow Worcestershire as the latest winners of the trophy, while Yorkshire, who have lost their last eight semi-finals, must wait another year to try and end their long wait for a first List A final since they won the old C&G Trophy in 2002.
Haynes, who was playing his first game since July because of injury, told Radio Nottingham: “It would obviously be nice to have a carrot of a home final, but we’ve got a big game ahead of us first on Sunday at Grace Road.
“From the position we were in, we dragged it back brilliantly with the ball from the start they got.
“No matter how long it’s been, you always think, ‘Have I forgotten how to bat or not?’ So, it was nice to hit a couple out of the middle. And Kyle, with his class, made it a lot easier for me.”
Yorkshire head coach Anthony McGrath added: “We would have bowled had we not lost the toss. We knew it was probably going to get easier. We were in a great position, 194-3 with about 12 overs left. Really, we should have got 300. That would probably have been enough.”