Porcello pitched three-hit ball for seven innings, Ryan Raburn hit two home runs and the Tigers beat the Blue Jays 10-4 Sunday.
Porcello (7-11) won consecutive starts for the first time this season. He walked none and struck out four.
"He pitched extremely well," Tigers manager Jim Leyland said. "He looked like he was in total command. His presence from the start looked impressive."
Porcello said his confidence got a boost after several Blue Jays swung and missed his slider in the early innings.
"They're such a good fastball hitting team, I knew going in I had to have a good off-speed pitch, whether it was my changeup or my slider," Porcello said. "Early on I felt pretty good with my slider, felt like I could locate it well. That was pretty much what we went with the entire day."
In his last outing, Porcello shut out Kansas City on two hits for seven innings.
"Porcello did an unbelievable job," infielder Brandon Inge said. "He was kind of just cruising through the game, using a good fastball and letting his movement take over. It was a good game. We needed one like this."
Before the game, the Blue Jays honored former right-hander Stieb, who threw the only no-hitter in franchise history 20 years ago this week, beating Cleveland 3-0 on Sept. 2, 1990.
Raburn hit a solo homer off the facing of the second deck in left field against Jesse Carlson in the seventh, then added a three-run shot off Brian Tallet in the eighth that made it 10-1. Raburn has 10 homers this year, and it was the fourth multihomer game of his career.
"He's a more relaxed and better player than he was last year," Leyland said. "He's starting to understand that he belongs up here. Like I've said many times, if he thought as much of himself as we think of him, he'd be a real good player."
Raburn is batting .341 with eight homers and 21 RBIs in his past 23 games. Half his hits in that span have been for extra bases, including seven doubles.
"That's how it goes sometimes," Raburn said. "I'm a real streaky guy anyway. Once I get in a hot span, it seems to click for a couple of weeks."
Inge hit a two-run drive in the seventh for the Tigers, who have connected in 11 straight road games, hitting 24 home runs in that stretch.
John McDonald hit a solo homer off Porcello and Adam Lind added a three-run shot off Jose Valverde in the ninth. Toronto leads the major leagues with 197 homers this season, including a majors-high 112 at home.
Phil Coke worked a perfect eighth before Valverde gave up four hits in the ninth, including Lind's 19th homer.
Porcello set down the first 11 batters in order before Jose Bautista lined a two-out single in the fourth, leaving Leyland to wonder whether another no-no might trump Stieb's celebration.
"The thought crossed my mind," Leyland said.
Porcello retired six of the next seven, with Aaron Hill reaching on an infield single to third base in the fifth, before the light-hitting McDonald ended the shutout bid with a two-out homer in the sixth.
It was the first homer allowed by Porcello since Alex Rios of the White Sox connected off him on Aug. 3.
The hit gave Cabrera 300 total bases this season, making him the fourth player in Tigers history to record 300 or more total bases in three straight seasons.
The Tigers added a run in the fourth on an RBI single by Casper Wells.
Detroit chased Rzepczynski in the sixth, two batters after a two-run double by Wells, then tagged Carlson for three in the seventh on homers by Raburn and Inge.
Rzepczynski struck out eight in 5 2/3 innings.
Blue Jays SS Yunel Escobar (back) did not start. ... Tigers DH Johnny Damon was held out of the starting lineup. ... Toronto announced RHP Brandon Morrow will be shut down for the season following his next start, Sept. 3 at New York. Morrow has pitched a career-high 143 1/3 innings this year, his first full season as a starter. ... Former Blue Jays Jesse Barfield, Tony Fernandez, Pat Hentgen and Duane Ward joined Stieb on the field for the pregame ceremony.