The Red Sox needed just one hit in that inning to take the lead, a cushion that came in handy when John Lackey (4-1) struggled through six innings before three relievers held the Blue Jays hitless. Jonathan Papelbon worked the ninth for his ninth save in nine chances.
Boston trailed 4-2 heading into the second and led 6-4 after the wild streak by Morrow (2-3).
Dustin Pedroia's RBI single made it 7-4 in the third. Jose Bautista hit a two-run homer, his seventh, to cut it to 7-6, but Toronto lost for the second time in nine games. Boston is 6-2 in its last eight.
Morrow had tied the club record of four walks in an inning on April 9 in his debut with Toronto after being traded by Seattle on Dec. 23 for Brandon League. In 35 innings this season, Morrow has 26 walks and 46 strikeouts. In his previous two starts, he struck out nine batters each time, a career high. On Monday, he had four strikeouts and allowed three hits in 1 2/3 innings.
The Red Sox took a 2-0 lead before Morrow recorded an out. Marco Scutaro led off the first with a walk, Pedroia doubled and both scored on Victor Martinez's single. Morrow then struck out the next three batters.
The Blue Jays went ahead with four runs in the second before Lackey retired a batter. They loaded the bases on a walk to Lyle Overbay, a double by Alex Gonzalez and a walk to Bautista. John Buck then doubled in two runs, and Travis Snider and Fred Lewis singled in one each.
Then came Morrow's meltdown in the bottom half.
Boston loaded the bases on walks to Jeremy Hermida, Jonathan Van Every and Scutaro. Pedroia also walked, forcing home a run with one out. Martinez then grounded to shortstop Gonzalez, who threw to second for a forceout. But Aaron Hill's throw to first trying for an inning-ending double play sailed into Boston's dugout for an error as Van Every and Scutaro scored.
The Red Sox then drew their fifth walk of the inning, by Kevin Youkilis, before David Ortiz's RBI single gave them a 6-4 lead, chasing Morrow and bringing in Josh Roenicke.
Lackey retired the first two batters in the fifth before Gonzalez singled and Bautista homered with two outs. But Lackey retired the next batter and finished his night with a perfect sixth.
Boston RF J.D. Drew was a late scratch from the starting lineup with vertigo. … Josh Beckett's next start was pushed back two days to Friday night in Detroit to give him time to work on his problems. He's allowed at least seven earned runs in three of his last four outings. Tim Wakefield will take his place Wednesday against Toronto. … With the bases loaded this year, Blue Jays pitchers have issued seven walks and hit two batters with pitches. … Umpires reviewed Gonzalez's hit near the top of the left-field wall and stuck with their original decision of a double instead of changing it to a homer. … Red Sox CF Mike Cameron went 1-for-3 with a double and a walk in a rehab appearance for Triple-A Pawtucket, his first game since being sidelined by a lower abdominal strain.