The left-hander said while warming up he saw no indication of the struggles he would experience.
"I felt fine in the bullpen -- I threw a no-hitter in the bullpen," Duensing said. "I don't know. Somehow it just didn't transfer today. It was just a really bad day."
After talking things over in the dugout after the first, Duensing said he felt confident he could weather the storm. But the second inning wasn't any better as he surrendered four runs, allowing three home runs in four at-bats to Jonny Gomes, Cespedes, and Carter. Duensing threw 67 pitches by the time the inning was through, and it was his last as Casey Fien came on from the bullpen to begin the third.
"He was just flat across the zone," Twins manager Ron Gardenhire said. "They beat it around. ... He just couldn't put a hitter away and couldn't finish off a hitter. Ends up getting us in a hole, and it kind of went from there."
It was the fourth straight loss for Duensing, who entered with a 7.15 ERA in three starts this year. Sunday's outing saw his ERA as a starter climb to 10.13.
Minnesota's bullpen was taxed by the rough start, as six different Twins relievers combined to throw seven innings. Fien used the opportunity to impress, throwing three shutout innings while allowing only one hit.
Gardenhire needed four innings out of his bullpen on Saturday after De Vries allowed seven runs in five innings.
"Long innings and then you're deep into your bullpen again, which is really hard," Gardenhire said. "Casey did a heck of a job for three innings of coming in, speeding the game back up, getting it rolling again."
Darin Mastroianni scored Minnesota's first run in the first on Josh Willingham's fielder's choice hit at Oakland starter Jarrod Parker. Parker tried to start a double play by getting Joe Mauer -- who singled -- out at second, but committed a throwing error. Alexi Casilla drove in Ryan Doumit with a sacrifice fly in the second.
Justin Morneau and Trevor Plouffe extended their hit streaks to 13 games with back-to-back singles in the sixth. Both eventually scored, Morneau on Doumit's double and Plouffe on Brian Dozier's groundout to second. Plouffe's streak is a career-best while Morneau's season-best streak is the second longest of his career.
Parker wasn't at his best, allowing four runs on nine hits in six innings, but he was efficient. The early lead made his job easier.
"It's great to pitch with a lead," Parker said. "We've swung the bats all series, and it makes it a lot easier. I got away with some mistakes -- they put together some hits -- but when you have the run support we did early, you give up runs for outs, and I was trying to do that."
Seth Smith homered off Jeff Gray in the sixth to give Oakland its second-straight game with four home runs. Smith, Carter and Cespedes combined to go 14-for-33 with six home runs and 12 RBIs in the series.
The A's order in no way resembled the same one that scored just six runs in a three-game sweep at the hands of the Twins on May 28-30. Oakland scored 24 runs in these three games.
"They got some good pitches to hit and they didn't miss them," Dozier said. "One through nine, they absolutely murdered the ball this weekend. Hats off to those guys."