PHOENIX (AP) — A couple of small mental errors had a big impact on the Mets.

“We think we have a chance,” Mets manager Terry Collins said after the Arizona Diamondbacks beat his club 5-3 on Sunday to complete a three-game sweep. “We get in the eighth inning and down a run, we felt really good. Then they scored that extra run in the bottom of the eighth. That took a little but of the starch out.”

Even worse from Collins’ point of view was the way in which Arizona scored. Ryota Igarashi loaded the bases on a walk, a hit and a hit batter before walk to Henry Blanco to drive in a run.

“We’ve got to throw strikes and we are not doing that,” Collins said. “We have to pitch better. This game is all about pitching and always will be about pitching. If you don’t pitch you are going to get beat.”

Through an interpreter, Igarashi said: “Today I was pushing too much. I rushed my pitches. My mechanics were way off.”

Lucas Duda had two hits, including a home run, and drove in two and Angel Pagan went 3 for 4 for the Mets, who have lost five straight.

Collins also was upset with Jason Pridie getting picked off first base after leading off the sixth with a bunt single down the left side of the infield.

“You’ve got a 3-2 count, you can’t get picked off on that and Jason knows that,” Collins said. “Those are the little things that come back and haunt you. Up here you can’t make those mistakes and right now our lineup is such that we can’t make mistakes.”

Mets starter Chris Capuano (9-11) allowed four runs on nine hits over six innings with six strikeouts, but couldn’t hold either a 2-1 lead or keep the Diamondbacks from breaking a 3-3 tie.

Paul Goldschmidt snapped a 3-3 tie in the sixth inning, doubling to the left-field corner and scoring on Blanco’s double to left.

Justin Upton tied the game at 3 with a solo homer deep into the left-field stands in the fifth.

“I felt like I threw the ball pretty well but I certainly made some mistakes,” said Capuano, who has lost four of his last five decisions. “I felt like I gave up some runs that I need to get, especially that last one. I hung that change-up to Blanco with two outs. That is a tough way to come out of the game.”

Diamondbacks right-hander Jason Marquis left the game in the fourth with a broken fibula after taking a line drive off his shin one inning earlier.

Pagan hit a line drive off Marquis’ right shin with two outs in the third but the right-hander remained in the game at first.

An inning later, Marquis hit Josh Thole with a pitch and dropped to the ground after his delivery, clutching his right shin.

He rolled over and rose to one knee but continued holding his right ankle until he was checked out by medical staff and limped off the field.

Arizona manager Kirk Gibson said Marquis would be out for four to six weeks.

Zach Duke (3-4), who came on in relief of Marquis, allowed two runs on four hits over 2 2-3 innings and David Hernandez pitched the ninth for his 11th save in 13 chances.

Upton and Blanco each finished with two hits for the NL West-leading Diamondbacks, who remained two games ahead of the San Francisco Giants.

Duda gave the Mets a 1-0 lead in the fourth with a solo homer to right off Marquis before he had to leave.

In the bottom half of the inning, Goldschmidt hit a ground-rule double that hopped over the left-field bullpen fence to tie it and Sean Burroughs later came home on a wild pitch to put Arizona in front 2-1.

Goldschmidt’s double snapped a streak of five consecutive strikeouts for the rookie first baseman.

Justin Turner hit an RBI double in the fifth off Duke and scored on a one-out single by Duda to give the Mets a 3-2 lead.

NOTES: Gibson said he’ll discuss with GM Kevin Towers and his staff how to fill Marquis’ spot in the rotation. Micah Owings, who pitched the seventh in relief Sunday and has started previously, is one possibility but Gibson said “I like the bullpen the way it is. I really like my bullpen.” . Mets RHP Mike Pelfrey, who left Saturday’s start after taking a line drive off his right elbow, had X-rays and is set to make his next start. … The Diamondbacks are 15 games over .500 for the first time since 2007, the year they won the NL West. … Five of Arizona’s nine hits were for extra bases. The Diamondbacks lead the NL and are third in the majors with 383 extra-base hits. … The Mets have lost five straight road games. . Capuano’s zero-walk game was his sixth of the season and first since June 29 at Detroit. … David Wright doubled in the first to extend the Mets’ streak to 12 consecutive games with at least one double. … After an off-day Monday, Arizona RHP Josh Collmenter will face Philadelphia ace Roy Halladay on Tuesday at Citizens Bank Park. … Mets RHP R.A. Dickey, 2-4 in his past 10 starts, will make his first career start in San Diego’s Petco Park on Monday.

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