Johnson barreled into catcher Jeff Mathis, who held on to the ball to preserve the win.
"I knew it was going to be close," said Johnson, who walked away with five facial abrasions and cuts to his hands and knee. "Wish I could have gotten a little better shot on him, but it's his job to get it and get out of there as best as he can, so he did a good job there."
Sierra, who put the Blue Jays on the board with a solo homer -- his third of the season -- in the third inning, was all smiles after the game.
"I feel great. I feel good because I tried to help my team, and made a good throw to home plate," said Sierra, who's batting .286 over 25 games.
Before the ninth-inning drama, the night belonged to Morrow.
Morrow was making just his second start since June 11, but showed no side effects from the oblique injury that forced him to miss over two months. The right-hander has allowed three earned runs over 11 1/3 innings since returning from the disabled list, while walking two and striking out 12.
Before he was forced to the sidelines, he was enjoying a breakout season, where he not only morphed into Toronto's ace, but one of the best pitchers in baseball at the time he suffered the injury.
Morrow was 7-4 with a 3.01 ERA and three complete-game shutouts when he hit the shelf. Despite the two-month recovery, his three shutouts are the second most in the Majors.
The only blemish Morrow allowed Friday was a solo homer to Desmond Jennings to lead off the third, which gave the Rays an early 1-0 lead. Jennings' homer snapped Morrow's streak of 62 1/3 innings without allowing a homer, which was the longest streak for a Blue Jays pitcher since Rogers Clemens went 96 consecutive innings in 1998.
Following the homer, Morrow went on to retire 12 of the next 15 batters he faced before Jennings hit a two-out double in the seventh.
Farrell felt one key was that Morrow got a better feel for his curveball after Jennings took him deep in the third.
"I think it allowed him to relax a little bit, rather than just try to go with sheer power stuff throughout, and it gave him that velocity separation that we saw, pre-injury, that made him so effective," Farrell said.
Morrow agreed with Farrell and thought he succeeded by changing speeds, and felt his curveball was important because he didn't do a great job at locating his fastball, although he did run it up to 97 mph.
"I felt good the whole way. After the first couple innings, my pitch count was climbing, but I settled in and started locating better with the offspeed stuff," said Morrow, who improved to 8-5 while lowering his ERA to 2.93.
Morrow allowed one run on eight hits, walked one and struck out five. He threw 102 pitches after throwing 88 his first start back from the DL. He felt his stamina was fine and is not concerned about the oblique, either.
"I knew through the rehab process that I was putting it behind me and I could feel my body becoming more confident, I guess, that I wasn't going to re-injure it," Morrow said.
The 28-year-old has been downright dominant in his eight victories, allowing just four runs -- good for a 0.64 ERA -- and 38 hits.
Morrow had a lead to work with after Ecnarnacion broke open a tie game by crushing a 1-0 fastball from Rays starter Jeremy Hellickson into the second deck in left-center field to put the Blue Jays ahead, 2-1. It was Encarnacion's 35th home run of the season and 90th RBI, both of which are career highs. He has hit five homers in his past 13 games.
Encarnacion has been a force all season. The 29-year-old has posted an OPS of at least .800 in every month this season. His lowest mark was .808 in May, but he also hit nine homers and drove in 21 runs that month.
Hellickson was chased in the seventh after Encarnacion recorded his second hit of the game with a single to left. The Rays righty lasted six-plus innings, allowing two runs on four hits, walking one and striking out a pair. He fell to 8-10 on the year.
Steve Delabar struck out the side in the eighth before Casey Janssen closed things out in the ninth, recording his 19th save of the season.
Toronto has won three consecutive games for the first time since July 26-28.