Iwakuma, meanwhile, outpitched Samardzija with four scoreless frames. Samardzija began the day with three shutout innings, before allowing a run each in the fourth and fifth.
Iwakuma and Samardzija might not be considered aces within their respective pitching staffs. (There's no shame at all in following Felix Hernandez or Chris Sale.) But they'd each sit atop a good number of Major League rotations, and they showed why on Tuesday.
The White Sox threatened against Iwakuma in the bottom of the third, when J.B. Shuck recorded a one-out bloop hit that dropped just behind the pitcher's mound. Micah Johnson, who remains among the Cactus League's batting average leaders, followed with a single, but Iwakuma stranded both runners in scoring position by getting Melky Cabrera to fly out and Jose Abreu to pop out.
"I'm not 100 percent there yet, but I'm getting closer," said Iwakuma, who threw 60 pitches, 43 for strikes. "I feel like I'm in game mode now. Hopefully, now it will pick up another notch."
Shuck, who had a pair of hits, replaced center fielder Adam Eaton in the lineup after Eaton was a late scratch because of a stomach bug. Johnson filled Eaton's role in the leadoff spot.
James Jones and Robinson Cano added RBI hits in the fifth for Seattle. An inning later, after Morrison tripled, Dustin Ackley drove in a run with another three-bagger to make it 4-0. In the seventh, Ketel Marte had an RBI double.
Adam LaRoche drove in a White Sox run with a booming double off of Yoervis Medina in the sixth inning. Andy Wilkins added another with a sac fly in the seventh. Geovany Soto had an RBI groundout in the eighth before Trayce Thompson launched a game-tying, two-run homer off of Rafael Perez.
"I liked his last at-bat," White Sox manager Robin Ventura said of Thompson. "I think he puts a lot of pressure on himself. He's got a ton of talent, [he's a] good kid and I think he just needs to go out and play with the confidence that he should have. He can do everything on the field."
Up next: Jose Quintana looks to continue his hot start to Spring Training on Wednesday when the White Sox travel to Goodyear to face the Reds at 3:05 p.m. CT, live on Gameday Audio. In three starts this spring, Quintana has posted a 1.35 ERA. He's allowed just four hits in 6 2/3 innings, while striking out eight. Meanwhile, Jesse Crain, on the long road back from a 2013 shoulder injury, will pitch in a Minor League game.