SEATTLE -- Nine starts in, and the curious case of Justin Dunn continues.

The Mariners’ righty again battled his pitch count Saturday at T-Mobile Park, but he put Seattle in position for a 3-2 victory over the Rangers that sealed a series win in the four-game weekend set. This came on a night when he received just one run of support while on the hill.

Mitch Haniger’s straightaway solo shot in the eighth was the difference in Seattle’s fifth win in its past six games, continuing a promising offensive trend after a tough seven weeks to begin the season.

• Box score

The Rangers -- or, more specifically, Adolis García, as he has all season against the Mariners -- made it interesting in the ninth by reaching on an infield single and scoring on a sacrifice fly. And Joey Gallo, who represented the tying run, made it to third base, but Rafael Montero was able to seal the save.

Dunn gave up just two hits, both singles -- both to García -- the last representing his final batter. He struck out eight and surrendered one run, lowering his ERA to 3.18, and extending his American League-best streak of 15 straight starts allowing three runs or fewer. Opposing hitters are now batting .168 against the right-hander, second-best in the AL to only Chicago’s Carlos Rodón.

“I think the biggest thing is my process, right now,” Dunn said. “I'm really happy with my process, really happy with my routine and the work I've been putting in between starts with [pitching coach Pete Woodworth] and our catchers, and doing a great job there. And on the field, just attacking hitters and making them put the ball in play.”

Dunn also pitched into the sixth inning when his night looked like it could be over after five frames and 89 pitches. That total was, in large part, due to a 31-pitch fourth inning, in which he hit his first batter, walked his second, then walked another with a strikeout in between. Thanks to the defense and some weak contact from Texas, Dunn worked his way out of that bases-loaded, one-out jam with one run allowed.

“I just got back to pitching,” Dunn said. “I had a little mechanical cue that was off there in the fourth and sat down and kind of went back into my thoughts and had my reset and realized what that was. And I just got back to attacking the strike zone and pitching, first and foremost. Glad I was able to find it and get through the fifth there and help us get a little deeper in the game.”

It’s all been a very similar theme for Dunn, who again flashed some impressive breaking balls -- take your pick, the curve and slider were both as sharp as ever on Saturday -- and 95-plus mph heat with life. But the 25-year-old again came just shy of pitching a full six innings, a threshold he hasn’t reached since Sept. 6 of last year.

Granted, Dunn is a much-improved pitcher since the last time he went that deep, and despite some of his hiccups, he’s shown tangible steps forward -- such as putting himself in a trustworthy enough position to go back out for the sixth -- an opportunity that might not have been afforded to him as recently as last month.

"I think that we just know that he's going to keep you in the ballgame,” Mariners manager Scott Servais said. “And he's understanding how to get deeper in games and what that does for your team, and certainly your bullpen. It has been a struggle, at times, to try to figure out where we're going to go. But with young starters, seeing them grow, it's very gratifying because they're only going to get better, if we can keep these guys healthy and keep moving forward. They’re learning so much.”

Obviously, the elevated pitch count in the fourth played a huge part on Saturday, but he’s now thrown 45 1/3 innings this season over nine starts, an average of just over five per.

By standard and advanced metrics, Dunn ranks first or second among all Mariners starting pitchers in just about every statistical category -- except innings.

ERA: 3.18 (1st)

ERA+ (park neutral): 117 (1st, entering Saturday)

K%: 23.4% (2nd)

WHIP: 1.19 (2nd)

Opposing BA: .167 (1st)

Innings: 45 1/3 (4th)

“Finish,” Dunn said of his mentality going back out for the sixth. “I'm very thankful to get to that point in the game, and the big thing was to finish. I've gotten there a couple of times this year and haven't been able to finish and wasn't able to again tonight. But I was a lot closer and I felt really good about where I was at, and I just want to keep taking those strides. Take away that one inning there in the fourth and continue to get better and get deeper into ballgames. But overall, I was really happy with the outcome.”