Gutierrez hit a pair of bookend homers as the Cannons earned their first victory of the season and avoided a series sweep.
After losing close games on Friday and Saturday, the Cannons put together a 15-hit attack on get-away day and overcame a four-run deficit. Gutierrez, who went 3 for 4 and drove in five runs, also hit a two-run homer in the first inning.
Doubles by Chris Williamson and Chris Denorfia staked Potomac starter Steve Kelly to a 3-0 lead, but the Avalanche struck for three runs in the fourth and two in the fifth.
They added three more in the seventh against reliever Travis Thompson and led 8-4 before the Cannons came back.
Fernando Rios, Mike Calitri, Williamson, Denorfia and Brian Peterson had two hits each for Potomac, which has today off.
The Cannons host Myrtle Beach in their home opener on Tuesday.
Nathan Cotton picked up the first win of the season for Potomac’s pitching staff with two innings of no-hit, shutout relief.
Mike Trembley, who earned a save in Salem’s opening night win, failed to register an out on Sunday. He came in to start the bottom of the ninth with a three-run lead, but was greeted by a Peterson single and a Denorfia double. William Bergolla pulled Potomac to within 8-7 with a two-RBI single.
After Jeff Bannon walked, Gutierrez belted the game-winning blast off Salem reliever Brandon Roberson.
Ninth-inning rallies were a common theme in the season-opening series. On Saturday night, the Avalanche scored four runs in their final at-bat to stun the Cannons, 4-3.
All four runs came off Cannons reliever Kyle Edens, who was making his professional baseball debut.
Edens inherited a 3-0 lead when he took the mound, but the right-hander retired only one of the seven batters he faced.
Bannon hit a solo homer and Peterson drove in two runs for the Cannons.
Starting pitcher Clayton Andrews left the game after five innings with a no-hitter intact. Andrews walked one, struck out three and faced 16 batters one over the minimum in his league debut.
Kyle Stanton and Casey DeHart worked one scoreless inning each for Potomac.