By pitching a scoreless eighth inning during the Red Sox's 13-5 win over the Rays, Timlin made career relief appearance No. 1,050, passing Kent Tekulve for first on the all-time list.
For the 42-year-old Timlin, it was a meaningful milestone.
"Quite humbling," said Timlin. "It's been something I've been kind of eyeballing all year long. It's been slowly coming. I've been just trying not to be too excited about it. It's a goal I've been working for for a long time."
Left-hander Jesse Orosco holds the all-time relief record with 1,248 appearances.
"There's no way I'm catching Jesse Orosco," said Timlin. "I'm just going to try to take it as far as I can take it."
The season has been a struggle for Timlin, who has a 5.96 ERA.
A key member of the Boston bullpen since 2003, there's a strong chance Timlin will retire after the season. But he doesn't want to make anything like that official at this point in time, especially with Timlin chasing his fifth World Series ring, and the Red Sox attempting to win their third in the past five seasons.
"I've done some thinking on that," Timlin said when asked about 2009. "I want to finish this year and do what I have to do here. There's things I want to finish this year. You start thinking about being done or retiring or what you're going to next year, you can't plan it. I want to finish this job first."
With Tropicana Field located roughly 30 minutes from Timlin's offseason home, this was the perfect place for the righty to make history.
"It's nice to do it here with a lot of people that I know [at the game]," Timlin said. "Obviously, you can't plan things like that. I appreciate that [manager] Terry [Francona] got me in there. I had a lot of people here at the game."
Timlin was very appreciative of everything that has gone into reaching the milestone.
"It's a blessing from God," Timlin said. "I'm 42 years old; I'm still throwing in the low 90s. He's given me the ability to go out there and do what I do every day, and I'm just trying to honor that."
And Francona, who isn't typically one to prioritize individual accomplishments, was pleased that the perfect spot came up to get Timlin into Monday's game.
"We wanted to get Timlin in there," Francona said. "We knew the significance of that. That's a tremendous achievement. That's a lot of appearances."
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.