"He plays the game the right way," said Scherzer, who roomed with Oeltjen at Triple-A Tucson last season. "He plays it hard. He is always hustling. He always takes the extra base. Right now, he's on fire."
Oeltjen has 12 hits in his first 24 at-bats since his contract was purchased from Triple-A Reno to replace the injured Justin Upton on Aug. 6. He has hit safely in all five of his major league games. Oeltjen also made a stellar catch in center field.
Oeltjen, a native of Sydney, Australia, singled and scored in a three-run third inning capped by Alex Romero's two-run single. He tripled and scored in the fourth for a 5-2 Arizona lead.
"Every day I still pinch myself, is it real or is it a dream," Oeltjen said.
Oeltjen batted in the eighth inning with a chance to become the fourth player in Arizona history to hit for the cycle.
He lined a single off pitcher Brian Stokes' glove into center field on the first pitch he saw after singling in the third inning, tripling in the fourth and doubling in the sixth.
"I'd be lying if I said it wasn't in the back of my mind," Oeltjen said.
Said Arizona manager A.J. Hinch: "That's another tribute to his style; he has a chance for the cycle, but he stays within himself and gets his ho-hum fourth hit of the game."
Scherzer (7-6) gave up two runs in 6 2/3 innings for his first victory in three career outings against the Mets. He struck out eight and did not issue a walk for the third time in his 29 major league starts while winning for the second time since June 23.
"I was just trying to avoid the big inning," Scherzer said.
Arizona (52-62) has won nine of 13, and five of six against the Mets this season after taking three of four at Citi Field from July 31-Aug. 3. In taking the first two games of the three-game series, Arizona has won three of its last four series.
New York has lost 10 of 13 after a five-game winning streak. Following a 27-20 start, the Mets have gone 25-41 since May 29 and fallen nine games under .500 for the first time since ending the 2004 season at 71-91.
"It gets to a point where it is about your pride now. It is about guys stepping up and doing what we have to do for the team," Francoeur said. "The last two-three weeks haven't gone the way we wanted it to, and it is time to get back to winning some games."
The Mets were 1 for 8 with runners in scoring position, left a runner on third base with one out in the first inning, and committed two errors -- by shortstop Cora and second baseman Luis Castillo. They had two errors in the first game of the series Monday.
"We have to play good, sound fundamental baseball. We get an opportunity, we have to pick up a run here or there," manager Jerry Manuel said. "As of right now, I don't know if I have many (lineup) choices, but I will sleep on some things and go from there."
Mets right-hander Livan Hernandez lasted only four innings, giving up six hits and five runs. Hernandez (7-7) has given up 34 earned runs in his last 36 innings, raising his ERA to 5.28.
Mets third baseman David Wright was held out of the starting lineup, although he pinch-hit in the ninth inning, striking out to end the game. "Physically he is a little down. A cold," Manuel said. Wright, hitting .322, has played in 112 of the Mets' 113 games this season. ... Arizona signed two draft picks Tuesday, supplemental first-rounder Christopher Owings and 13th-rounder Patrick Schuster. Owings received a $950,000 signing bonus. Schuster, who threw four consecutive no-hitters at Mitchell High in New Port Richey, Fla., last spring, received $450,000. Arizona recalled left-hander Daniel Schlereth, their No. 1 pick in the 2008 draft, after placing left-hander Scott Schoeneweis on the disabled list because of depression.