"Nobody wants to lose 100 games in a season," Nelson said. "Just to get done with that ... Now that's over with. Just finish the season strong."
Rockies manager Jim Tracy said he is encouraged by small victories, even if one of them is avoiding triple figures in the "L" column.
"That game tonight exemplifies what I've been saying endlessly over the course of the last few weeks or so about the effort that you've gotten from a group of young kids for the better part of over two months now," Tracy said.
Nelson has been a bright spot through the struggles.
Since the All-Star break, Nelson has sizzled with a .344 batting average. Nelson had a double in the 11th, but did not score because DJ LeMahieu followed two batters later by grounding into a double play.
After Blackmon's single made it 5-3 in the 13th, LeMahieu beat third baseman Chris Johnson's throw to the plate on Jonathan Herrera's grounder and Matt McBride scored on Mike Zagurski's wild pitch for the final two runs -- insurance that proved critical in the bottom half of the inning.
Josh Outman (1-3) entered in the bottom of the 12th with two out and two on and struck out Jason Kubel.
But Outman walked two in the bottom of the 13th, and the Rockies needed Josh Roenicke to get the final two outs for his first career save, after the D-backs scored twice and brought the potential winning run to the plate.
"We certainly shouldn't have done what we did in the bottom of the 13th inning -- three or four base on balls after taking a four-run lead," Tracy said. "I just can't comprehend that. I can't compute that."
Rockies starter Drew Pomeranz matched his season high with seven strikeouts in five innings, and the Rockies took a lead into the ninth. But the D-backs' Eric Goldschmidt homered off closer Rafael Betancourt with one out in the ninth to tie it at 3-3. It was Betancourt's sixth blown save in 37 chances.
Regardless the result, Pomeranz's season finish also was notable. He won his previous start, at home against the Cubs, and followed that up with a strong effort to finish his campaign.
Pomeranz gave up a pair of solo homers, to Aaron Hill (his 25th) in the first inning and Gerardo Parra (his seventh) in the fifth, but lowered his final ERA to 4.93. The no-decision left his record at 2-9.
"I feel really good about what he's done in his last couple of starts as he moves into the offseason," Tracy said. "His ball-strike ratio tonight was terrific."
The Rockies trailed 2-0 when Wilin Rosario hit his 28th home run of the season in the seventh. He has exceeded the team's rookie record for homers, previously held by Todd Helton (1997), by three.
D-backs starter Wade Miley, considered higher on the list of NL Rookie of the Year candidates than Rosario, held the Rockies scoreless for 6 1/3 innings before Rosario took him deep.
The Rockies took a lead in the eighth with consecutive two-out RBI doubles by Josh Rutledge and Colvin against Miley.
"He threw the ball great," D-backs manager Kirk Gibson said of Miley, who struck out 10 in 7 2/3 innings. "I let him go longer than I probably would've normally, but it was his last start. Usually in those situations, you don't let a guy lose a game like that, but Wade wanted to pitch so I let him go, it ended up biting us. He threw the ball well."