Verlander won his 10th straight start and earned his 22nd victory overall, helped when Martinez hit a late grand slam that sent the Tigers over the Cleveland Indians 8-6 Wednesday.
The AL Central-leading Tigers completed a three-game sweep and won their sixth in a row.
"What a great win," said Verlander, who leaped off the bench and cheered Martinez's shot that highlighted a five-run rally in the seventh inning. "When he hit it, I said, 'It's that kind of year.'"
Verlander leads the majors in wins and is 20-2 since May 1. He gave up four runs and three hits in six innings, striking out eight.
"My stuff was not as crisp as it has been," Verlander said. "The two pitches to Duncan were pretty good, where I wanted them. Guys in this league get paid to hit it, too.
"Once again, our team came through in a huge way. They got big hits and I'm always extremely confident in our bullpen."
Verlander is the first Detroit pitcher to win 10 consecutive decisions since Jack Morris in 1983, and first to win 10 straight starts since Hall of Famer Hal Newhouser in 1946. His 22 wins are the most for a Detroit pitcher since Joe Coleman went 23-15 in 1973.
"They didn't get many hits off him, just a couple out of the ballpark," manager Jim Leyland said.
"That's his job and he's doing it pretty well," Leyland said. "Don't forget what (Joaquin) Benoit did in the eighth."
The Tigers' setup man struck out two in a perfect inning and has a 1.58 ERA over his last 43 outings.
Martinez went 5 for 13 with two homers and 10 RBIs in the sweep of his former team as Detroit dropped Cleveland 9 1/2 games back. The Tigers are 16-4 since Aug. 19, going 6-0 against Cleveland and sweeping three in a row from the Chicago White Sox to take command of the division.
"They took care of business and, obviously, we didn't," Indians manager Manny Acta said. "They're doing a great job running away from us."
Leyland isn't ready to celebrate.
"Have we accomplished something? Absolutely," he said. "So far we've met a head-on challenge pretty good. I told them, 'Have a good day off (Thursday). You earned it. But get ready to play Friday because nobody is going to give us anything.'"
Masterson left after Detroit loaded the bases on two singles around Duncan's error at first base in the seventh. Joe Smith came on and yielded Miguel Cabrera's RBI single that got the Tigers within 4-3.
Lefty Tony Sipp replaced Smith and the switch-hitting Martinez turned around to the right side and hit the first pitch into the left-field seats for his second career slam, both against the Indians. The first was Oct. 3, 2009, for Boston, a couple of months after Cleveland traded him to the Red Sox.
"It's not just because it's against the Indians, I always want to do my best," Martinez said.
Martinez, Cabrera and Alex Avila each had two of Detroit's 13 hits. The Tigers have had 10 or more hits in 11 of their last 13 games and 31 of 51 games since the All-Star break.
"We were kind of up and down for a while and are starting to hit our stride," Verlander said.
Duncan had his second two-homer game this week and fourth of his career. He also did it Sunday in Kansas City.
He came in just 2-for-11 (.182) with four strikeouts in his career against Verlander before connecting in the second for a 2-0 lead. The two runs were more than the Indians scored in seven of Masterson's starts this year.
Detroit tied it at 2 in the fourth. Cabrera singled with one out for the Tigers' first hit and was doubled to third by Martinez. Cabrera scored on a sacrifice fly by Avila and Wilson Betemit doubled home Martinez.
Jim Thome lined a two-out double high off the wall in left-center in the Indians' fourth. Duncan followed with his eighth homer, a towering shot to left for a 4-2 lead.
Verlander has thrown at least six innings and 100 pitches in all 31 starts this season. ... Fans sitting in a dreary drizzle throughout the game got a few laughs in the middle innings as a squirrel darted around the outfield. ... Indians DH Travis Hafner, out since Aug. 22 with a strained tendon in his right foot, ran in the outfield before the game. "Just straight ahead, nothing lateral, but I'm feeling better," he said. ... Detroit is 21-10 on the road since July 6, best in the AL. ... Cabrera has hit .391 with 26 RBIs while reaching base safely in a career-high 34 consecutive games, the longest streak by a Tigers player since Damion Easley's 34-game streak in 1998. ... The Tigers are off Thursday before playing host to Minnesota for three games. ... The Indians start a four-game set in Chicago on Thursday in a chase for second place. LHP David Huff (2-3) will oppose White Sox RHP Gavin Floyd (12-10).