"You always want to beat the team you just played for," Cust said Thursday before going out for batting practice in his old haunt. "You've got buddies over there. Nobody wants to lose to the team you were just with. You're hoping you're going to a team that is better. That's what it comes down to.
"I just want to go out and do the best I can, and hopefully the team can win some ballgames here."
Cust could help in that effort if he gets on track early. The Mariners signed him as a free agent in an effort to add some pop to an offense that finished last in the American League in nearly every offensive category last season.
The 6-foot-1, 247-pound Cust hit 97 home runs over the past four seasons for Oakland. Of his 102 career home runs, 55 have come at the A's park and his batting average (.266), slugging percentage (.501) and OPS (.910) are considerably higher there than his career marks of .245, .452 and .830.
"This is a place I've always felt comfortable, so it's good we open up here," he said.
But he also knows what the Mariners are getting into as they square off against Trevor Cahill, Brett Anderson, Gio Gonzalez and a quality A's bullpen over the next three days.
"They've got a good staff, one of the best in the league, and they're going to be tough to beat with that pitching," Cust said. "And they've got good defense. We need to go out and manufacture some runs and hopefully get to some of those pitchers early."