Millwood allowed two hits and struck out a season-high 10 over eight innings as the Rangers beat Cleveland 5-2 on Sunday and ended the Indians' five-game winning streak.
"I don't know if I threw (the curveball) any better, I just used it more," Millwood said. "They've been trying to get me to use it more. I threw it (Sunday) more than ever."
Mark Teixeira helped Millwood with a three-run homer that capped a five-run seventh.
Millwood (14-9) retired the first 14 batters before Kevin Kouzmanoff, who hit a grand slam on the first pitch he saw in the majors Saturday night, homered in the fifth.
Victor Martinez's two-out double in the seventh was the only other hit Millwood allowed.
In addition to a fastball in the low- to mid-90s, Millwood mixed in his curve and slider to keep the Cleveland hitters at bay.
"An outing like this will build confidence in his curveball," Texas catcher Gerald Laird said. "He threw inside a lot and his curve kept them all off balance."
Through six innings, it appeared Millwood was going to be outdueled by Cleveland starter Paul Byrd.
Byrd (9-7) was working on a shutout before Texas scored five runs in the seventh.
The Rangers opened with three straight singles off Byrd, and Gary Matthews Jr. had a run-scoring groundout to tie it at 1. Michael Young put the Rangers ahead with an RBI single.
Byrd was relieved by Fernando Cabrera, who gave up Teixeira's three-run shot on a 1-1 pitch. It was Teixeira's 25th homer of the season, and 16th since the All-Star break.
Byrd allowed four runs and 10 hits in 6 1/3 innings, struck out one and didn't walk a batter.
"I thought I threw great," Byrd said. "It was one of my best games of the year. They did a good job in the seventh of just putting the ball in play."
The Indians were looking to match their season-best winning streak. Cleveland is 18-6 since falling a season-worst 17 games under .500 on Aug. 8.
The Rangers, who had lost eight of 12 coming in, finished their homestand with a 4-5 mark.
Millwood, who won the American League ERA title last season with Cleveland before signing with Texas, struck out seven and allowed just one ball out of the infield before Kouzmanoff's homers ended Millwood's perfect streak to start the game.
"I wasn't even thinking about that," said Kouzmanoff, who was recalled from the minors before Saturday night's game. "I was going up there like it was another at bat."
Millwood struck out the side in the third and fanned two batters in the fourth and sixth innings.
After Martinez's double in the seventh, Jhonny Peralta walked. But Millwood got of the inning unscathed when Kouzmanoff fouled out.
"Kevin is a veteran pitcher we can lean on," Showalter said. "He seems to be getting stronger as the year goes along."
- DH Travis Hafner missed his second straight game with a bruised right hand. Hafner was hit by a pitch Friday night and his status is day-to-day
- Millwood faced the Indians on April 29. He got the win by allowing just two hits in seven innings.
- Texas C Rod Barajas missed his third straight game with a bad back.