Tyler Murray scored 21 points, including a 3-pointer with 1:43 remaining, to lead Wagner in a 58-54 win over Stony Brook on Sunday.
The Seahawks (2-1) trailed 48-47 with 2:58 left, before Murray's long-range shot gave them the lead for good, 50-48.
Wagner made 40 percent of its 3-point shots (6 of 15), with Murray making 3 of 4.
The Seahawks were also efficient from the free-throw line, going 18 for 19 (94.7 percent).
Wagner held the Seawolves (3-2) to just 7 field goals in the second half, as they finished shooting 23.8 percent from the field (15 of 63).
Despite their poor shooting, the Seawolves stayed in it by winning the battle of the boards 49-30 and scoring 20 second-chance points.
Danny Carter had 14 points and 11 rebounds for Stony Brook. Bryan Dougher scored 15 points and Dallis Joyner added 13 rebounds for the Seawolves.