PHOENIX -- Facing Colorado Rockies closer Rafael Betancourt with two outs in the bottom of the ninth, Arizona's second baseman guessed fastball and was rewarded.
Not that Aaron Hill did anything different than normal.
"I'm always waiting for a fastball," Hill said after his game-winning three-run home run off Betancourt lifted the Diamondbacks to a 5-3 victory over the Rockies on Tuesday night. "You live by the sword, you die by the sword."
Hill's second career walkoff home run and first since 2006 assured the Diamondbacks of a non-losing season. A win on Wednesday would give the Diamondbacks an 82-80 record and consecutive winning seasons for the first time since 2007-08.
"Winning never gets old," said Arizona manager Kirk Gibson.
John McDonald hit a one-out single to left off Betancourt (1-4) and Gerardo Parra singled to left one out later. Hill then drove the first pitch he saw into the left-field stands for his 26th home run of the season.
"You give Aaron first and third and you could see what's going to happen with how good of a hitter he is," McDonald said. "The bullpen's been awesome all year for us so it was nice to be able to give them something back."
Brad Ziegler (6-1) pitched the ninth for the victory.
It was the second blown save in as many nights for Betancourt.
"You've got your closer out there and you've worked the game to the point where you go to the eighth inning with the lead," said Rockies manager Jim Tracy. "(Rex) Brothers did a terrific job (in the eighth) and if they are going to beat us, they have to beat those people. They got our closer."
The two starters, Jhoulys Chacin for Colorado and Patrick Corbin for Arizona, allowed only one run between them before turning things over the bullpens.
McDonald hit a two-run home run off Guillermo Moscoso in the seventh to give the Diamondbacks a 2-1 lead.
But Colorado came right back in the eighth.
Josh Rutledge led off with a single to left off David Hernandez. Tyler Colvin doubled to left and Pacheco lined the first pitch he saw down the left-field line, scoring both runners for the 3-2 lead.
Chacin was nearly untouchable before reaching the Rockies' 75-pitch limit on their starting pitchers. The right-hander gave up three hits in five scoreless innings, throwing exactly 75 pitches, while striking out four and walking two.
"I felt really good today," Chacin said, "even in the first inning when I couldn't get the ball down. I was throwing a little bit up and then I got my feeling for all my pitches."
Chacin finished 3-5 with a 4.43 ERA in 14 starts and 69 innings after missing more than three months with right shoulder inflammation.
"I felt really fresh and that's a good sign," Chacin said.
Corbin pitched into trouble only once and it translated into the Rockies' first run of the game.
Andrew Brown led off the second with a single and advanced to third when Parra bobbled DJ LeMahieu's single to center. Corbin induced Charlie Blackmon to ground into a double play, allowing Brown to score for the 1-0 lead.
After Jonathan Herrera followed the double play with a double to left, Corbin settled down to retire 12 straight hitters and 16 of the final 19 he faced.
"The last game he was trying to come in on people and he couldn't locate in there," Gibson said. "Today he commanded the fastball more on the inside part of the plate. He had good life and better velocity."
Corbin went seven innings and allowed one run on six hits. The rookie left-hander struck out six and issued an intentional walk.
"That's what I wanted to do was end on a good note, go into the offseason feeling good about this year and get ready for next year," Corbin said. "I'm sure in the offseason that I'll take it all in but it was a great first year in the big leagues."
The Diamondbacks took their first lead in the seventh. Jason Kubel doubled off the base of the right-field. Chris Johnson grounded out to third but McDonald followed with a towering home run into the back of the Diamondbacks' left-field bullpen for his sixth home run, matching a career high set in 2010.
NOTES: Kubel's double made him the seventh player in franchise history to hit 30 home runs and 30 doubles. ... Corbin has allowed only three unintentional walks in his past six starts spanning 26 1/3 innings. ... The Rockies came into the game with only four of seven players on the bench healthy enough to play. ... Diamondbacks C Miguel Montero singled in the fourth for his career high 139th hit of the season. ... RHP Ian Kennedy (15-11) closes out the season for the Diamondbacks on Wednesday against Rockies LHP Jeff Francis (5-6). Kennedy is 4-0 with a 3.00 ERA in his past six starts but walked six batters, the second-most of his career, in his last start Friday against Chicago. Francis is 8-7 in 23 career starts versus the Diamondbacks.