Given new life after the Dodgers misplayed what should have been an easy pop foul out with two outs in the third inning, Clark tied the game with a two-run, opposite field homer to left.
The NL West-leading Diamondbacks went on to hand the Dodgers their sixth straight loss, 12-3.
"You don't give TC second chances," Arizona's Mark Reynolds said.
Clark -- an old-timer among a roster full of youngsters -- drove in four runs altogether.
"I'm glad to be in the middle of it," Clark said, "but any given night anybody can be in the middle of it."
Arizona's lead in the NL West climbed to 1½ games over second-place San Diego, which lost 2-1 in 14 innings to Colorado.
Chris Young and Reynolds also hit two-run homers as Arizona scored 11 in a row after falling behind 3-1. Augie Ojeda tripled and doubled, scoring both times in the Diamondbacks' third victory in a row and fourth in five games.
"We've got an outstanding group of guys, who happen to be young, and yet happen to be very talented," Clark said. "The combination platter has been an absolute pleasure to be a part of."
The third inning miscue occurred when Clark hit a high pop foul off third base. Nomar Garciaparra moved in place for what should have been a routine catch but was called off by shortstop Tony Abreu at the last minute.
Garciaparra ducked, and the ball hit the ground between the two players. Moments later, Clark hit his 16th home run of the season and it was tied.
"Recently, whenever we have made mistakes, we've had to pay severely for them," Los Angeles manager Grady Little said. "That's just the way it goes when things are happening for your club like they are right now."
As Clark rounded the bases, Garciaparra glared at the young Abreu. The Dodgers clubhouse was closed for 30 minutes after the game for a team meeting.
When a reporter asked about the subject of the meeting, Little said, "We would have invited you to the meeting if we wanted you to know what it was about."
The Dodgers have allowed 36 runs in their last four games, a rough ending for a team that was picked by many to win the division.
"It's a lot of frustration, understandably so," Little said. "But it's like everything else in life, you deal with it."
With the Dodgers clearly out of it, Little said he would field some different lineups in the remaining games.
Clark also drove in a run with a ground out in the first and had an RBI single in Arizona's four-run sixth.
"He's been pretty good for us every time we've plugged him in in big games," Arizona manager Bob Melvin said. "He's always in a prominent spot in the lineup. We get a lot of stability from him, a presence from him, a lot of production from him."
Ex-Diamondback Luis Gonzalez earned his 2,500th career hit with a line shot single off the first baseman Clark in the seventh. Even though Gonzalez was the most popular player in Diamondbacks' history and holds virtually all the franchise offensive records, there was no recognition on the big video screen or the public address system.
"Orlando Hudson, a couple of guys over there acknowledged me," Gonzalez said. "And some of the fans. I played here a long time."
Livan Hernandez (11-10) gave up three runs and 10 hits in six innings and had an RBI single.
Los Angeles starter Esteban Loaiza (1-3) retired the first two batters in the fourth before Ojeda tripled to the left-center gap. Hernandez's soft single to left brought home Ojeda for a 4-3 Arizona lead, then Young lined an 0-2 pitch into the left field stands. The rookie's 31st home run of the season put the Diamondbacks up 6-3.
Six hits and two walks led to four Arizona runs in the sixth, and the rout was on.
The Dodgers got the leadoff batter on base in each of the first three innings and scored a run each time to go up 3-1.
Jeff Kent, who complained about some of the Dodgers' work habits after Thursday night's loss at Colorado, was 3-for-4 with an RBI and a run scored.
- A dust storm swirled through the stadium in the second inning. The Chase Field roof was closed in the top of the fourth, after the storm had passed.
- SS Rafael Furcal was out of the Dodgers' lineup for the fourth game in a row because of a sore lower back.