MINNEAPOLIS (AP) — The Minnesota Twins were cautiously optimistic heading into the All-Star break, thinking their best baseball of the season was ahead of them after a competitive road trip to Detroit and Texas.

Three games into the unofficial second half, they have slid back to 16 games under .500 and appear to have little chance of climbing out of the AL Central cellar.

Brian Duensing served up the latest dreadful start by a Twins pitcher, giving up six runs and seven hits in just two innings as the Oakland Athletics completed a three-game series sweep with a 9-4 victory on Sunday.

It was the worst-case scenario for the Twins, who only got five innings from starter Cole De Vries in a loss on Saturday night.

"Their guy did his thing and shut us down but it all goes back to the starting pitching," manager Ron Gardenhire said. "We used in two games here about 11 innings out of our bullpen. That's not the way you go about your business so when you get that deep into your bullpen you're in a lot of trouble."

Yoenis Cespedes homered and drove in three runs and Jarrod Parker gave up four runs in six innings for the Athletics, who have won nine of 11 and took a little revenge for a three-game sweep at Target Field in May.

Ryan Doumit had a double and an RBI, but the Twins had a heck of a time getting good wood on Parker's offerings. The right-hander yielded nine hits and received a boost from Oakland's suddenly formidable offense.

Jonny Gomes, Chris Carter and Seth Smith also connected for the A's, who racked up 24 runs and nine homers in the sweep after scoring just six runs in losing three in a row in Minnesota in May.

"It's fun to watch and I think it's coming together," Parker said. "Throughout this lineup anybody can hit the ball out. There are so many threats now. It's fun to watch."

Duensing (1-6) was primarily to blame this time around, setting the tone for a long day at the ballpark with an exhausting first inning. The left-hander, who was making his fourth start after being moved back into the rotation from the bullpen, needed 41 pitches to record three outs.

Cespedes had an RBI single and Carter walked with the bases loaded to give the A's a 2-0 lead.

"It was a bad day, basically," Duensing said. "And a quick one."

Laboring through the inning clearly sapped the lefty, who was making his fourth start after moving from the bullpen. Without much juice on his offerings, the Athletics pounced in the second.

Gomes hit a two-run shot to left field, Cespedes went deep to straightaway center and Carter's solo shot went off the facing of the second deck in right-center to give the A's a 6-1 lead and draw boos from the home crowd. Duensing needed 67 pitches to get through the two innings and didn't have enough left to come out for the third.

"Forty pitches in the first inning is too long," Gardenhire said. "Just couldn't put a hitter away and couldn't finish off a hitter. Ends up getting us in a deep hole and kind of went from there."

Casey Fien pitched three shutout innings, but the Twins still had to use seven pitchers in the game, including closer Glen Perkins in the ninth when they were down 9-4.

"Our offense is doing the job, our bullpen is doing the job," Duensing said. "The starting pitching right now is really struggling and not putting our team in a good spot."

The Twins (36-52) are one loss away from matching the most games under .500 for the season. They fell 13 games behind the White Sox in the division and are losing more and more hope by the day.

"We have to start figuring out how to win them and not lose them," Gardenhire said.

NOTES: Athletics OF Coco Crisp rested for the second day in a row because of a sore left shoulder he aggravated on Friday night. He's listed as day to day. ... The last time the A's hit three HRs in one inning was June 17, 2008, at Arizona when Bobby Crosby, Rajai Davis and Mark Ellis went deep during the ninth in a 15-1 win. ... Twins DH Justin Morneau extended his hitting streak to 15 games with a single in the sixth. ... Newly signed Minnesota Wild forward Zach Parise threw out the first pitch before the game. The Minnesota native recently signed a 13-year, $98 million contract to play for his hometown team. ... The Twins will open a series against Baltimore on Monday night, with LHP Scott Diamond (7-3, 2.62 ERA) facing Orioles RHP Chris Tillman (1-0, 0.00). ... The A's head home to face Texas. Colon (6-7, 3.80 ERA) will face Rangers RHP Roy Oswalt (2-1, 6.26).