"It felt good to pick up the pitching. They've picked us up a bunch this year," said Cust, who homered in the first inning to snap a career-long, 40-game drought. "If we can get our bats going we should be better."
In his first game off the disabled list, Thome homered twice -- including a 465-foot shot that bounced high in the air after landing on the Target Field pavilion in the fourth inning.
He also hit a line drive that had just enough height to clear the wall in left field in the seventh.
The slugger took a curtain call after his second homer, and the Twins held a 7-4 lead. But again, the bullpen couldn't hold on.
"You go on the DL and you go down, you always want to come back and swing the bat well," Thome said. "Unfortunately, we didn't win the ballgame. That's what you want to do every night. It felt good to swing the bat good, but ultimately, it's all about winning."
Jack Wilson led off the 10th with a single against Anthony Swarzak (0-2) and moved to second on Miguel Olivo's single. Ichiro Suzuki advanced both runners with a sacrifice, and Chone Figgins was intentionally walked. Wilson scored on Rodriguez's fly to center.
"There were so many moments in that game which were turning points," Mariners manager Eric Wedge said. "Ultimately, there were three or four things that if we don't do what we need to do, we're not playing any more."
Brandon League pitched a perfect inning for his 11th save in 14 chances.
Denard Span also went deep for the Twins.
Capps escaped the eighth, but Peguero lined a two-out single to center in the ninth to score Saunders from second and tie it at 7.
Capps had a chance to catch Saunders too far off second base on a comebacker to the mound with one out, but failed to make the throw.
Twins manager Ron Gardenhire removed his hat in disgust in the dugout, something he has done often as his team continues to make uncharacteristic mental mistakes.
Shortstop Trevor Plouffe also had a couple of blunders.
"Mistakes. We talk about it all the time, the fundamentals -- get the outs you're supposed to. We didn't do that and it overshadowed a great night by Jim Thome," Gardenhire said.
Seattle and Minnesota are the two weakest hitting teams in the American League, but combined for 15 runs and 25 hits on Monday.
"Pitching has been the reason why we've run this streak," Wilson said. "It was nice to be able to swing the bat after the relievers kept us in the game."
It was the first time in eight games that the Mariners allowed more than two runs and the first time in nine games that a Seattle starter failed to pitch at least seven innings.
Vargas was 3-0 with a 1.47 ERA in his last four starts before Monday.
"He just didn't have the command that we've seen him have," Wedge said. "I'm just glad that his teammates were able to pick him up."
The entire Twins team circled around a large No. 3 behind second base to honor Harmon Killebrew during a pregame ceremony. The Twins will hold a public memorial service for Killebrew at 7 p.m. at Target Field on Thursday. ... Minnesota's Michael Cuddyer (right hip tightness) and Young (bruised leg) were removed after the seventh for precautionary reasons. ... Seattle does not have a player hitting above .300 in its starting lineup. ... An MRI exam on Twins RHP Kevin Slowey's oblique did not reveal any damage, but he wasn't available. Slowey might be sent to Triple-A Rochester or traded so he can again become a starter. ... Minnesota C Joe Mauer and 2B Tsuyoshi Nishioka are rehabbing in Florida and could see game action later this week.