Shenandoah (13-8) earns the league's automatic bid into the 24-team NCAA Tournament field with the win. The NCAA will announce the tournament field Sunday and first round games are scheduled for Wednesday.
Payne inserted a penalty corner to Hayes, who came right back to Payne on the doorstep where she knocked it past W&L (13-7) goalkeeper Ariyel Yavalar.
In the 57th minute, Morgan Lingo scored unassisted to give Shenandoah some breathing room.
The Generals pulled Yavalar in response, electing to play with an empty net and an extra attacker for the final seven minutes of the game.
W&L had two corners and two shots after pulling Yavalar, but the SU defense blocked the first shot and goalkeeper Jessica Brown recorded her seventh and final save to preserve the two-goal margin.
Washington and Lee outshot SU 16-4 and took 10 of the 11 corners in the contest. Shenandoah's only penalty corner of the game resulted in the game-winning goal.
"I am just really proud of this team," head coach Ashley Smeltzer-Kraft said. "The first time we played them, the outcome wasn't in our favor but we plugged away and made it happen.
"We battled for 70 minutes tonight. I thought we defended very well and stuck to our game plan. We did a great job of getting back on defense."
Notes: The win is the record-setting 13th of the season for the program... This is just the second-ever ODAC title in school history. Baseball won the first for the department in 2015… Field hockey becomes the seventh program in the department to earn an NCAA bid. Baseball leads with seven trips while men's basketball has been three times, women's basketball twice and football, women's soccer and softball one each.