PHOENIX -- For a while, the Pittsburgh Pirates were in another game that could go either way - the kind that led them to an 8-16 start.
Then they began a feeding frenzy unlike anything they've seen for a while.
Matt Lawton hit his first grand slam in six years in the eighth inning and added an RBI double in the ninth, and the Pirates beat the Arizona Diamondbacks 16-2 Sunday for their fifth win in six games.
"We're starting to play a little bit better," said Lawton, who had his last grand slam when he drove in six runs for Minnesota at Cleveland on April 17, 1999. "We're trying to score runs early, trying to get leads.
"That's what we've been doing - jumping on guys early and trying to ride it out."
The Pirates scored 12 runs in the final two innings, seven against Kerry Ligtenberg in the ninth.
Daryle Ward hit a three-run homer during the ninth, Jack Wilson had a two-run single, and Rob Mackowiak had a run-scoring single. The Pirates set season highs for runs and hits (17).
"You're going to have streaks like this during the course of the year," manager Lloyd McClendon said. "You're also going to have the ones like we had to start. It's just baseball. The good thing is when you survive that type of close start and start to come out of it, you realize that you're OK and can compete."
Ty Wigginton had three hits, including his first homer of the year, Humberto Cota had a two-run double, and Kip Wells worked seven solid innings for his third straight win.
Wells (3-3) gave up two runs and four hits, including a solo homer by Luis Gonzalez, and walked three. Gonzalez drew one of the walks and scored Arizona's first run on Chad Tracy's fourth-inning sacrifice fly.
But Wells had runners on second and third with nobody out in the fourth after Troy Glaus doubled, but then struck out Shawn Green and Koyie Hill around Tracy's run-scoring fly to center. An inning earlier, he walked opposing starter Brad Halsey and then went 3-0 on Craig Counsell.
"He popped up to third," Wells said. "For me, that was one of the biggest turning points to keep me off the ropes. That really kind of helped me right the ship, and the next pitch I get a double-play ball."
The Diamondbacks, who had two hits in a 3-2 loss Saturday night, had only six in this one.
"I think as a group, in this series we didn't do a good job swinging the bats," Counsell said. "Everybody's just got to take it upon themselves to be a better hitter."
Pittsburgh put away the game in the eighth, scoring five runs after Diamondbacks reliever Jose Valverde walked the first two batters and allowed a pinch-hit single to Freddy Sanchez.
Bobby Hill, pinch-hitting for Wells, had an RBI single off Javier Lopez to reload the bases before Lawton drove the first pitch into the right-field seats for his fourth grand slam.
"We got our butts kicked this series," Arizona manager Bob Melvin said. "It's going to happen from time to time. We've got to rebound."
Halsey (2-1) lost for the first time in seven starts.
Winless in three starts since beating San Diego 5-3 on April 22, Halsey allowed four runs, seven hits and an uncharacteristic four walks in 6 2/3 innings.
He had issued only three walks in 35 innings coming in, but struggled with his control from the start.
Halsey walked Lawton, his first batter, leading to Jason Bay's sacrifice fly.
In the second, Halsey got one out before Wigginton's opposite-field shot cleared the fence in right.
It remained 2-0 until the sixth, when Jose Castillo lined a single to left and Wigginton beat out an infield hit. Cota, a catcher whose improvement in his second full season gave manager Lloyd McClendon the option of releasing Benito Santiago on Sunday, then lined a double into the left-field corner. Both runners scored when the ball rolled away from Gonzalez along the bullpen fence.
The Pirates put OF Craig Wilson on the DL before the game and purchased the contract of Ray Sadler from Double-A Altoona. Sadler made a spectacular catch for his first major league putout, chasing Gonzalez's opposite-field liner to the left-field line and then nearly doubling up Alex Cintron at first base. ... Bay doubled twice to extend his hitting streak to seven games. ... Arizona CF Jose Cruz Jr. (sore back) began a rehab assignment by playing five innings for Triple-A Tucson.