But any worries disappeared when Dunn hit his National League-leading 33rd home run, powering the Diamondbacks to a 7-6 victory over the San Diego Padres on Tuesday night.
"It's a good feeling to have," Dunn said. "Probably Opening Day and the opening day of deer season are about the only times I get butterflies."
Conor Jackson had two hits and two RBIs for the Diamondbacks, who have won four of five and six of eight.
Arizona starter Doug Davis (5-7) scattered seven hits over six innings for his first win since July 29, and his second win in his last nine starts. Tony Pena recorded the final two outs for his second save -- and first since May 16 -- in five chances.
"I ended up getting strike one more often tonight and was able to make them hit my pitch," said Davis, who has recorded three of five wins against the NL West.
Adrian Gonzalez had four hits and two RBIs for the Padres, who have lost five of seven.
Dunn, acquired by Arizona from the Cincinnati Reds on Aug. 11, made it 6-2 with a towering two-run homer in the fourth on a pitch Padres starter Josh Banks said he "tried to bounce." Dunn tied Philadelphia's Ryan Howard for the NL lead and moved within two homers of Carlos Quentin of the Chicago White Sox for the major league lead.
"I knew it was going to come and my homers come in bunches," Dunn said.
San Diego made things interesting in the ninth against Diamondbacks closer Brandon Lyon, who has struggled in non-save situations over the past month.
Trailing 7-3 entering the inning, Edgar Gonzalez doubled, Brian Giles drew a one-out walk and Kevin Kouzmanoff singled to right to load the bases. Adrian Gonzalez followed with a sinking line drive to center, scoring his brother and Giles to pull the Padres within 7-5.
Chase Headley then singled to right to make it 7-6.
"I don't think he's a guy who needs the emotional lift or adrenaline rush of a save situation," Arizona manager Bob Melvin said of Lyon, who allowed three runs to raise his ERA to 4.60. "He's just being a little bit fine with the fastball."
Lyon, pitching for the first time in nearly a week, gave way to Pena, who threw out Adrian Gonzalez at home on a fielder's choice and retired Nick Hundley on a fly ball to center to end the game.
"We put a nice finish on it," Padres manager Bud Black said. "Every hit in the ninth inning is big but we couldn't get that really big one at the end."
Banks (3-6) struggled with his control from the opening batter and Arizona capitalized.
Chad Tracy was intentionally walked and Chris Snyder hit a run-scoring single to make it 3-0. Chris Burke lifted a sacrifice fly to deep right to score Dunn for a 4-0 lead before Banks struck out Davis to end the inning.
"The team going out there and scoring four runs made it a lot easier to go out and throw strikes," Davis said.
Banks allowed six runs, four hits and a season-worst seven walks with three strikeouts over four innings. In his last two starts, Banks has walked 13 and allowed 13 runs in 8 1/3 innings.
"I know I'm letting the team down," Banks said. "That's just not how I pitch. I'm not the most dominating pitcher but usually I can keep my team in the game."
Gerut singled home Adrian Gonzalez in the eighth to pull San Diego within 6-3. Jackson added a run-scoring single in the bottom of the inning, his second RBI of the game, to make it 7-3.
Adrian Gonzalez's four-hit game was his third of the season and first since May 25. ... Davis' last win was also against the Padres, when he carried a perfect game into the seventh inning. ... Dunn's home run was his first since July 30. ... Kazmar's RBI was the first of his fledgling five-game career. ... Before the game, the Padres activated RHP Brett Tomko from the DL. San Diego signed Tomko as a free agent on June 27 but he made only two appearances before going on the DL July 8 with a strained right elbow. ... Tomko entered the game in the sixth and pitched 1 2/3 hitless innings.