He took in the moment prior to the at-bat, and then got down to business against Seattle's former star, who had already hit two home runs in the game.
"I kind of just got a good look at him, and said, 'This is cool,'" O'Flaherty said. "Then I went after him like any other hitter."
The result? An inning-ending strikeout. O'Flaherty worked a perfect seventh, and aided by a successful suicide squeeze in the bottom half of the inning, earned the win, improving his record to 4-0.
He's the fourth pitcher in club history to start 4-0, the first since Julio Mateo in 2004.
"As a reliever, it's more coincidence than anything else," O'Flaherty said of his perfect start. "It's random more than anything. It's just about being at the right place at the right time."
Although it may be true O'Flaherty has been called upon in the right situations, it's hard to ignore his 2.19 ERA and 0.97 WHIP (walks plus hits per innings pitched). In 24 2/3 innings this season, he has allowed six runs on 16 hits while walking eight and striking out 16.
The young southpaw's career statistics aren't much higher, posting a 2.78 ERA in 35 2/3 innings.
Still, O'Flaherty said he's really settled into his role as a reliever this year, mostly because he's more familiar with his surroundings than he was last season.
"Last year, I wasn't really sure of myself," O'Flaherty said. "This year, I've been there before, I've settled in, and I've just gone after guys this year instead of thinking too much."
Pressing the bench:
Mariners reserves Willie Bloomquist and Ben Broussard have seen more playing time than usual lately, filling in for injured outfielders Raul Ibanez and Jose Guillen.
If Sunday was a test for the usual reserves, they passed with flying colors.
Broussard tied Sunday's game with a ground-rule double in the sixth inning, and was hitting .305 with two home runs and four RBIs as a starter prior to Monday's game against the Red Sox.
He also hit the first pinch-hit grand slam in Mariners history on April 21 against the Angels.
Bloomquist laid down a perfect suicide-squeeze bunt in the seventh, allowing the game-winning run to score.
"The bench player probably has the toughest job in baseball," said manager Mike Hargrove. "He has to work extra hard and do all sorts of extra work to be able to maintain what it is that he has."
Both were still in Monday's lineup, as Ibanez continues to recover from a sore right hamstring and Guillen nurses a sore right arm.
A hit in Monday's game would give center fielder Ichiro Suzuki seven career 20-game hitting streaks. How many players in Major League history have seven or more streaks? See the answer below.
Lowe, Ramirez updates:
Reliever Mark Lowe and starter Horacio Ramirez have continued their rehabilitation programs and are inching closer to rejoining the rotation.
Ramirez threw three innings of a simulated game Monday.
"He threw the ball well," Hargrove said. "I don't know how many pitches, but he threw the ball well. His velocity was good."
Hargrove said he wasn't sure if Ramirez would throw any more simulated games before rehabilitation starts begin.
Lowe is expected to throw simulated games on Wednesday and Sunday before moving to possible rehab starts.
The Mariners are giving away Kenji Johjima bobblehead dolls to the first 25,000 fans at Friday's series opener against the Blue Jays, the third in a four-piece set this season.
The doll comes complete with a removable catcher's mask, the first time a Mariners bobblehead has come with accessories, spanning seven years since their first bobblehead giveaway in 2000.
Other dolls in the set include Ichiro, Felix Hernandez and Ibanez (Aug. 17).
The Mariners finished Interleague Play with a 9-9 record this season, marking the eighth straight season they haven't had a losing record against the National League.
Since 2000, the Mariners are 86-58 in Interleague Play, which is the third-best mark in the Majors.
And the answer is...
Five other Major Leaguers have recorded seven or more hitting streaks of 20 or more games: Willie Keeler (8), Ty Cobb (8), Pete Rose (8) and George Sisler (7).
The Mariners face the Red Sox again on Tuesday in game two of the three-game series. Ace Hernandez (4-4, 4.00 ERA) faces off against southpaw Kason Gabbard (1-0, 3.60 ERA) at 7:05 p.m. PT.