"I'm very aware of that. They got me," he said after his two-run, eighth-inning single against Daniel Bard lifted the Blue Jays to a 5-4 victory.
The native of Surrey, B.C., came up to the majors as a pitcher and started four games against the Red Sox for Baltimore, going 0-1 with a 6.63 earned-run average in 2006 and '07.
"I think the best chance I had was against (Josh) Beckett in our place," Loewen said. "I came out of the game (ahead) 2-1 in the sixth and they ended up winning it in the top of the ninth."
Loewen last pitched in 2008, when he retired and decided to make a Rick Ankiel-like switch. He then worked his way up through the Toronto system, this year hitting .306 with 17 homers and 85 RBIs for Triple-A Las Vegas.
He was brought up the Toronto and got his first major league hit, off the Red Sox, last week. He hit his first big league home run against the Orioles last weekend.
In Tuesday's 18-6 loss, playing centre field because of the team's injuries, Loewen took a home run away from Carl Crawford.
"It's been crazy," he said. "I didn't think I'd be playing this much but I come ready to play everyday, whether I'm in the lineup or not."
Loewen is 5 for 14 as a major league hitter. His hit Wednesday made a winner out of Ricky Romero (15-10).
"Amazing. It's crazy," said Romero, who went eight innings to beat Boston for the second time in less than a week. "Just to make that transition from a pitcher to a position player, you never really see that and he's done a tremendous job for us."
Just 3-10 in September, the Red Sox remained four games ahead of Tampa Bay in the AL wild-card race. Boston led the AL East at the start of the month and was nine games ahead of the third-place Rays, who lost 6-2 at Baltimore on Wednesday night.
After getting swept in a three-game series at Tampa Bay last weekend, Boston hosts the Rays in a four-game series starting Thursday night.
Boston led 4-2 in the eighth before Toronto came back against the hard-throwing Bard (2-8), who entered and walked Edwin Encarnacion and Kelly Johnson.
Mark Teahen bunted, and Bard's throw to first pulled Lars Anderson off the bag for a throwing error that loaded the bases.
J.P. Arencibia's RBI ground out cut the lead to 4-3, with third baseman Kevin Youkilis bobbling the ball and throwing to first. Loewen followed with a single to centre.
Romero allowed four runs -- three earned -- and six hits in eight innings. He improved to 8-1 in his last 10 starts.
Frank Francisco pitched a 1-2-3 ninth for his 15th save in 19 chances as the Blue Jays won for just the third time in nine games at Fenway Park this season.
Red Sox starter John Lackey gave up two runs and seven hits in 5 1-3 innings.
Toronto took a 2-0 lead in the first on consecutive run-scoring singles by Encarnacion and Johnson, but Boston tied it in the second when Ryan Lavarnway reached on a run-scoring error by Canadian third baseman Brett Lawrie and an RBI grounder by Jason Varitek.
Marco Scutaro hit a sacrifice fly in the third after Jacoby Ellsbury's triple, and Adrian Gonzalez homered into the Red Sox bullpen for a 4-2 lead in the sixth.
Lawrie, from Langley, B.C., was tagged out by Varitek in the sixth inning. Varitek held on and tagged out Lawrie, who came crashing in with his forearms while trying to score from third on Loewen's bouncer to second with the infield in. Varitek flipped over backward from the impact but kept the ball in his glove.
NOTES: Gonzalez left with left calf tightness after his homer. ... Lawrie left with a bruised knee. ... Red Sox DH David Ortiz missed his second straight game with muscle spasms in his back. "He really wanted to play today," manager Terry Francona said. "He woke up this morning and was real sore, but he's moving around better." ... The Red Sox honoured RHP Tim Wakefield with a brief on-field ceremony after he became the 108th player in major league history with 200 career wins in Tuesday's 18-6 victory over the Blue Jays. ... Francona was also honoured on the field for being elected to the National College Baseball Hall of Fame earlier this year. ... Toronto SS Yunel Escobar missed both games in Boston because of a bruised left arm. ... The Blue Jays have a day off Thursday before they attempt to stop the Yankees' CC Sabathia (19-8) from winning his 20th game. Brett Cecil (4-9) is scheduled to pitch for Toronto. ... Kyle Weiland (0-1) opens the series against the Rays' Jeremy Hellickson (12-10) on Thursday.