"I'm a little bit frustrated because I walked the first hitter in the inning," said Quintana, who allowed four runs (two earned) on seven hits over 5 2/3 innings, striking out four and walking two. "I think that's the reason for the bad inning."
Said White Sox manager Robin Ventura of Quintana's leadoff free pass: "He was pitching a fairly good game, and going through a part of the lineup and working counts."
Then there was a Logan Morrison popup just behind third base. Not quite routine, as Conor Gillaspie had to range back four or five steps to make the play.
But when Gillaspie got to the ball, it hit off his glove and fell in fair territory for his team-high 11th error. Quintana still was clinging to a 1-0 lead, only now was doing so with runners on first and second and nobody out.
"You've got to catch it. That's why it's an error," Ventura said directly. "He missed it."
Quintana went in search of a ground ball, looking to turn two of course, but mainly focusing on minimizing the damage. Instead, catcher Mike Zunino followed with his 18th home run of the season, coming on a 2-0 pitch, a no-doubter, three-run shot launched out to right field.
That blast by Zunino ended a streak of 199 consecutive batters faced by Quintana without allowing a long ball. Baltimore's Steve Pearce was the last player to take Quintana deep, in the sixth inning of a White Sox victory on June 24.
"I tried to throw a good pitch away, but the ball ran right down the middle," said Quintana, who lost for the first time since June 13. "But I think that's all, one pitch, that's all for the game."
"We've pieced together a lot of good at-bats the last three days, and we have a good feeling that we're going to score some runs," Zunino said. "We're not trying to push the issue, guys are trying to piece together good at-bats and when the opportunity comes, guys are trying to capitalize."
Chicago's offense over seven innings against Hisashi Iwakuma (10-6) basically was limited to Dayan Viciedo's 16th homer, a first-pitch, two-out shot in the fourth. Viciedo has homered in three straight games for the third time in his career and has four homers in his last six games.
Adrian Nieto finished with two of the remaining five hits for the team, with the White Sox unable to do any damage against Charlie Furbush, Yoervis Medina and Fernando Rodney (32nd save).
In the eighth, with Leury Garcia on first and two outs, Medina threw two 95-mph fastballs to Alexei Ramirez that he took for strikes. Medina followed with a curveball that not only buckled Ramirez's knees but snapped in the zone for strike three.
Adam Eaton, the team's spark-plug leadoff hitter and center fielder, also was lost on the first at-bat of the game. Eaton had missed Thursday's series opener after a second-inning wall collision at U.S. Cellular Field when chasing down Adam Rosales' homer Wednesday, but announced himself ready to return on Friday.
Eaton battled through a nine-pitch at-bat to start the game but barely could get out of the box after grounding out to third baseman Kyle Seager. He left with soreness in his rib cage and said postgame that he would know more about what was going on Saturday.
Friday's setback was the fourth in a row for the White Sox (55-62) and their sixth loss in seven games, a stretch in which the White Sox have been outscored by a 56-12 margin. They have allowed 71 runs (64 earned) in eight games since August 1.
In the second of this four-game set, the Mariners outscored the White Sox by a 4-0 margin in the fifth alone and it was good enough for the win. It was another if it can go wrong, it will go wrong moment for Ventura's crew.
"Q is pitching great and then walk, error and homer does him in," Ventura said. "Combination of we're not playing well, and we're playing a team that's playing well and everything seems to be going right for them.
"We have to keep grinding. It's that simple. When you're in a funk like this, you've got to dig down and be tough about it, come out and find a way to win."