It also doubled the Bucs' National League Central lead over the St. Louis Cardinals to two games.
Martin's heroics off the bench were an encore to the way he had come to the rescue the last time he'd sat out a start, the previous Sunday in Anaheim. On that occasion, Martin's pinch-single keyed the Pirates' three-run tying rally in the ninth, and his single in the 10th drove in the winning run of an eventual 10-9 decision over the Angels.
"I don't know if I'm getting used to it, but I'm enjoying it for sure," Martin said in a locker room of exhausted, but elated Pirates.
An improbably glorious season reached the midway point with the most improbable win yet in game No. 81, as six Pittsburgh relievers blanked the Brewers on two hits across the last 12 innings after the second-inning thunderstorm had ended starter Charlie Morton's day prematurely.
"A truly incredible job from everyone out there," manager Clint Hurdle said, repeatedly shaking his head for emphasis.
"Their pitching is outstanding," Milwaukee skipper Ron Roenicke said, joining the chorus." I see why their ERAs are where they are, because every guy out of the bullpen has good stuff. It's located well. They have off-speed stuff, fastballs, their pitching staff is really good."
Vin Mazzaro was first through the gate with five perfect innings, and winner Tony Watson brought up the rear with three more perfect frames. Justin Wilson, Bryan Morris, Mark Melancon and Jason Grilli each went an inning in-between.
The next man out of the bullpen, had there been a 15th inning, would have been Jeff Locke -- Tuesday's scheduled starter against Philadelphia who, as it is, was scratched from that assignment because he did warm up Sunday.
"I knew I was the last guy down there," said Watson, who went three innings for only the second time in his 145-game career, the first time since July 23, 2011. "I was just trying to keep Jeff Locke out of the game. Just wanted to give our team a chance, and Russ came through for us."
Martin's dribbled single up the middle off Francisco Rodriguez scored Gaby Sanchez, who had led off with a single deep into the second-base hole then got into scoring position with his first stolen base since May 6, 2012.
Sanchez does his normal damage with the bat, but that course was denied him in the seventh by Brewers left fielder Logan Schafer, who soared far above the fence to keep his drive out of the seats.
"Did that finish make up for that? No," Sanchez said, grinning. "Well, except for the fact we won anyway. That did make it all right."
This was the Bucs' third win in games from which its starter was forced out, by injury or by weather, before the completion of the third inning.
Silenced to that point on two fifth-inning hits, the Pirates had rallied to a 1-1 tie in the eighth against the third man out of Milwaukee's bullpen.
But this was not their classic rope-a-dope production. For a long time after Brewers starter Kyle Lohse had joined Morton on the outs, the Bucs were kept on the ropes by Tyler Thornburg, a righty fresh off Milwaukee's Minor League shuttle.
After they were blanked by Thornburg for five innings, the Pirates sprang to life in the eighth against Jim Henderson.
With one out, Starling Marte was credited with an infield single on his grounder off shortstop Jean Segura. When Marte took second on Neil Walker's groundout, Roenicke had a decision: pitch to Andrew McCutchen, or put him on the empty first base and have the right-handed Henderson take his chances with Garrett Jones, a dangerous left-handed hitter.
The Brewers decided to go after McCutchen, and he made them pay with a laser single to left to tie the game.
Thornburg went five innings, blanked the Pirates on two hits while fanning four and walking one, and had to convince eyewitnesses that he was the same guy who had arrived Sunday morning from Triple-A Nashville with a record of 0-9 and 5.79 ERA.
Mazzaro's efficiency -- he got 10 of his 15 outs on three pitches or fewer -- persuaded Hurdle into a most unusual non-move: after Clint Barmes broke up the Brewers' combined no-hitter with a two-out double in the fifth, Mazzaro was allowed to bat, even with the potential tying run standing on second.
The pitcher responded with a hard-hit single to right -- although it did not result in scoring, with Barmes held at third before Marte lined out to end the inning. And Mazzaro further endorsed the decision by going ahead to retire six more consecutive batters.
In a cruel twist, Barmes made his first start at shortstop in two weeks and not only muffed the first grounder hit to him, but had to watch it instantly turn into an unearned run.
With one out in the second, Barmes erred on a grounder by Yuniesky Betancourt, who subsequently took third on a single by Martin Maldonado and scored as Schafer laid down a safety-squeeze bunt.