The victory provided a lift for the Rangers, who tied the game with Prince Fielder's two-out, full-count home run off Steve Cishek in the top of the ninth, and won it on Rougned Odor's leadoff home run off Mike Montgomery in the top of the 11th.
With four wins in five games against the Mariners in the last nine days, the Rangers have opened up a four-game lead in the AL West.
But hold the celebration. There are still 100 games remaining in the regular season for both teams, and still plenty of challenges to face, including both of them looking for help in the rotation after the admission on Saturday afternoon that both Yu Darvish of the Rangers and Felix Hernandez of the Mariners have suffered setbacks.
Darvish, after three starts and 15 2/3 innings in his return from Tommy John surgery, was scratched from a Monday start in Oakland because of neck and shoulder stiffness, and will instead return to Arlington, Texas to be examined by Dr. Keith Meister.
The Mariners, meanwhile, admitted that the strained calf which forced Hernandez to the disabled list has been slow responding to treatment, and instead of the hope that Hernandez could miss only two starts he instead is now expected to be out until at least the All-Star break.
That's why Paxton has surfaced as such a key player for Seattle.
The loss of Darvish leaves the Rangers debating whether to move lefty Cesar Ramos back into the rotation, a role he filled prior to the activation of Darvish, or call up 37-year-old Kyle Lohse, who agreed to pitch for the Rangers' Triple-A Round Rock affiliate after not landing an offseason deal. He is 2-2 with a 5.86 ERA in five starts.
Paxton, however, has shown signs he's ready to break through at the big league level. In his last 12 2/3 innings, he has allowed two earned runs, walked three batters and struck out 17.
"I think that I figured out that I need to make some pitches early in the game, doesn't matter if it's the first inning, just got to use more than one pitch, more than just the fastball, as well as locating the fastball," Paxton said. "Getting it inside to those right-handed hitters is big for me. So I think I just have to continue to do that and watch my video, coming into the game with a plan with the catcher and be ready to go."
After back-to-back quality efforts, Paxton had made a strong impression on team officials with a more aggressive approach on the mound.
''I think it's important to pitch with an edge, especially where he's at in his career right now,'' Mariners manager Scott Servais said after his Monday start against Cleveland. ''He's at a point where he has an opportunity to really step up and earn something and be a big part of what we're trying to get done here.
''Sometimes you've got to pitch with a little chip on your shoulder and it certainly looked like he did that tonight. He knew we needed him and he pitched a good ballgame.''
After issuing back-to-back walks to Ian Desmond and Nomar Mazara to open the fourth, Paxton regrouped, getting an out when Mazara was hit by a Odor ground ball, inducing Ryan Rua to ground into a fielder's choice, and then striking out Fielder.
"I just got caught trying to be too fine on the corners and just had to get back in the strike zone and go after guys with my stuff, instead of nibbling at the corners early in the count," he said.
And after back-to-back singles by Mitch Moreland and Bobby Wilson, the 8-9 hitters in the Rangers' lineup, with one out in the fifth, Paxton answered by striking out the 1-2 hitters, Jurickson Profar and Desmond.
It's a starting point for Paxton, and a reason for hope for the Mariners.