MESA (Interstat) — Max Hartman went 3 for 3 with a home run and four runs batted in to lead Washington State to a 14-4 victory over San Diego State in the first game of a doubleheader Sunday at the Mountain West Conference Baseball Championship.

Hartman’s seventh homer of the season, a three-run shot in the seventh inning, capped a seven-run outburst that broke open what had been a tight game. The Cougars improved to 30-26 overall; the Aztecs fell to 36-24.

Scott Rienguette earned the win with 3 2/3 innings of hitless relief, striking out six. He entered in the bottom of the fourth with Washington State trailing 4-3, runners on second and third and one out, and induced a strikeout and a hit batter before fanning another batter to escape the jam. That sequence shifted momentum, and the Cougars never trailed again.

Dustin Robinson went 2 for 5 with two RBIs, Trevor Smith drove in three runs on one hit and Ryan Skjonsby added two hits and three RBIs for Washington State.

San Diego State’s Tyce Peterson homered in the second inning, his 15th of the season. Issac Araiza pitched 1 2/3 innings of scoreless relief for the Aztecs, allowing three hits and striking out one.

Washington State jumped ahead in the first inning. After a leadoff groundout, a bunt single and an infield hit put runners on base. A ground-rule double by Priest scored Roy, and Robinson’s fielder’s choice brought home Hartman for a 2-0 lead.

San Diego State answered in the bottom half. Jackson led off with a home run, and Trosky tripled before Farrell doubled to tie the game at 2-2.

The Cougars regained the lead in the second when Hartman walked with the bases loaded, forcing in a run. But Peterson’s solo homer in the bottom of the second evened the score again at 3-3.

After a scoreless third, the Aztecs took their first lead in the fourth. Farrell walked, stole second, advanced to third on a groundout and scored on a wild pitch to make it 4-3.

Washington State responded in the fifth. Roy singled and Hartman was hit by a pitch. After a foulout, Robinson doubled to right-center, scoring Roy. Skjonsby followed with a double to left-center, driving in Hartman and Robinson to put the Cougars ahead 6-4.

The Cougars added a run in the sixth on Smith’s sacrifice fly.

Washington State blew the game open in the seventh. Skjonsby singled, Obenour reached on a bunt error, Macleod singled in a run, and Northrop sacrificed. Smith doubled down the right-field line to drive in two more. Hartman then homered to deep right, scoring three. Robinson doubled and Skjonsby added a sacrifice fly to cap the scoring.

Defensively, Washington State turned two double plays, while San Diego State grounded into three double plays but could not overcome the Cougars’ 14-hit attack.

The game was the first of two scheduled Sunday. Washington State had defeated San Diego State 14-9 the previous day. The Cougars have won two straight after losing four of their previous five. The Aztecs have dropped two in a row after winning seven of eight.

No betting line or over-under information was available for this game.