There were more boos when he fanned in the first inning on Wednesday.
"They enjoy it I guess," Upton said. "They've enjoyed booing me the last two months, but heck I've got to give them something to cheer about. I haven't given them much to cheer about."
That changed in the fifth, as he blasted a 3-0 pitch over the wall in left-center, bringing the crowd to its feet.
"It was nice to see him come through in that situation," D-backs outfielder Chris Young said. "He got himself in a good count and stuck with his plan, and he really drove the ball. That's something he's been wanting to do lately, pull the ball left-center, drive one in the gap. I'm sure there's a lot more to come."
The D-backs sure hope that's the case, because they know if they are to put together a run at a postseason berth, they need Upton's bat to heat up.
That was one of the reasons that manager Kirk Gibson gave Upton the 3-0 green light with no outs and runners on first and second. In fact, Gibson said there was no serious consideration given to having Upton lay down a bunt in that situation.
"That's why you don't bunt him, and that's why you give him the 3-0 [green light] because you're hoping for something like what happened that will give him that feeling and give him his confidence back," Gibson said. "We need to get him on track, we all know it. That's why we did it. He got 3-0 and he put a good swing on it, and he got another hit after that, so that was great."
Upton left the game after the sixth when he suffered a cramp in his left calf while running from first to third. The injury is not expected to keep him out of the lineup.
Gibson has given his hitters the green light on 3-0 pitches more than any manager in baseball since taking over midway through the 2010 season, and it has paid off, particularly when it comes to Upton. In 17 career at-bats where he's put the 3-0 pitch in play, Upton is 10-for-17 with five homers.
"It's not that easy," Upton said of hitting with a 3-0 count. "You see a lot of guys get mad when they swing at bad pitches. You just have to make sure it's a pitch you can handle. You're not always trying to hit a homer, obviously you just want to drive the ball, so you make sure the pitch is in the zone."
Upton's homer was just one of six hit by the D-backs. In addition to Upton, Aaron Hill, Jason Kubel, Miguel Montero, John McDonald and Ryan Roberts all hit one each.
Roberts' homer was an inside-the-park shot, the first of his career at any level. The ball bounced off the wall in right-center and away from center fielder Michael Saunders, and by the time right fielder Ichiro Suzuki finally tracked it down Roberts was able to circle the bases complete with a head-first slide into home.
"The main thing I was thinking was run hard until somebody told me to stop," Roberts said. "It was exhausting to say the least, but after a couple of innings I caught my breath. It was special, it was awesome. I'm glad I didn't fall over when I was running the bases. A couple of times I almost tripped. My body was leaning forward and my legs weren't catching up."
The offensive outburst allowed Trevor Cahill (6-5) to come away with the win despite allowing six runs on nine hits over six innings. He struck out five, and didn't issue a walk.
The Mariners made things interesting in the eighth, as they scored four runs off of reliever Mike Zagurski to pull to within 14-10.
With the win, the D-backs captured the series against the Mariners, and they have now won seven of their last eight home games.