Astros interim manager Tony DeFrancesco wasn't sure at first if Marwin Gonzalez was safe or out at home plate in the ninth inning. In that tangle, it was hard to tell.

So he burst out of the dugout to protect his player, and at least take a shot at persuading home plate umpire Dave Rackley to rule the go-ahead run had scored.

No such luck. Gonzalez was ejected before he could get to the plate, and the call stood.

Ike Davis then hit his second homer of the day with one out in the bottom of the ninth, lifting the New York Mets to their first series win at home since early July with a 2-1 victory over Houston on Sunday.

"It was a bang-bang play. The umpire got it right, but I thought it could have went either way," said DeFrancesco, a former catcher. "It was a heck of a play by the catcher squashing him off the plate."

Rookies Jeremy Hefner and Lucas Harrell engaged in a crisp duel for seven innings. Hefner took a shutout into the ninth before giving up a tying double to Gonzalez.

Gonzalez then tried to score on Ben Francisco's single off Bobby Parnell (3-3) and Lucas Duda, recalled from Triple-A Buffalo on Sunday, made a strong throw home.

Catcher Kelly Shoppach took Duda's slightly high throw and stuck his left leg out to block the plate. Gonzalez tried to slide around him and reach back for the plate, but Shoppach used his body to prevent Gonzalez from slipping in a hand. Gonzalez jumped up and slammed his helmet down after being called out. He was tossed by Rackley.

"It was a great throw by Duda, giving us a chance to keep it tied," Shoppach said of Duda, who is often criticized as being a sub-par outfielder.

Davis' drive off Wilton Lopez (5-2) just cleared the top of the right-field wall — and the glove of a leaping Francisco — for the second game-ending drive of his career — a homer under the new Citi Field dimensions. He took a leaping 360-degree spin into his awaiting teammates at the plate.

"I thought I hit it a little better than I did. Outfielder kind of deked me a little bit," Davis said. "Thought I'd look like a fool because I didn't run out of the box. ... First one I got pretty good."

Davis connected off Harrell, his former teammate on the U.S. national team, leading off the fourth, launching a shot about halfway up the second deck in right to help the Mets snap a skid of six straight series losses at Citi Field. Since taking two of three from Philadelphia July 3-5, New York has gone 5-16 at home.

Batting .199 on July 4, Davis has lifted his average to .223 and he has 24 homers this season.

"It was a pitch down and in," Harrell said. "I tried to get it in but not down."

The Mets took two of three in the final series at Citi Field with Houston being a National League team. The Astros join the AL West next season.

The Astros have won just eight of their last 53 games.

At Buffalo, Duda worked on playing in left field after starting 80 games in the right for New York. Often looking lost in the field before he was sent down on July 24 because he was slumping at the plate, Duda couldn't come up with a difficult catch in the ninth that allowed Houston to tie it 1-all, spoiling Hefner's fine outing.

"I thought he looked great out there. He looks comfortable," manager Terry Collins said. "As far as that ball goes, he ran a long way for that ball. And any time you dive toward that wall, there's issues. I thought he did fine. Of course, he made a great throw, too."

Pinch-hitter Jose Altuve led off the ninth with a single and Collins chose to leave Hefner in. Gonzalez then hit a low liner down the left-field line. Duda made the long run and the ball hit of his glove as he tried to make the catch and avoid hitting the wall.

Altuve scored and Gonzalez landed on second base chasing Hefner.

Harrell came in the leader in innings pitched for rookies and had won 25 percent of the Astros' 40 games. He was second to Wade Miley in wins for rookies in the NL and led the league with 151 1-3 innings pitched.

He showed how good he was Sunday, giving up two hits and a run with four of his seven strikeouts coming with the batter caught looking.

"I felt like I was working quick and in the zone all day," Harrell said.

NOTES: RHP Armando Galarraga has chosen to become a free agent rather than accepting an assignment to the minors after being designated for assignment by the Astros last week. ... Astros OF Justin Maxwell missed his fifth consecutive start with a bruised right index finger. He will see a doctor Monday and could be headed to the disabled list.