The Red Sox beat the Seattle Mariners 8-2 last night but the real victory came more than two hours after the final out.

With the Red Sox fighting the Tampa Bay Rays for the division and everyone else for American League supremacy they fired the strongest salvo of trade deadline season swinging a three-way trade for Chicago White Sox right-hander Jake Peavy a three-time All-Star and former Cy Young Award winner. Peavy immediately fortifies a rotation that has produced despite the absence of All-Star Clay Buchholz.

“We’re really excited to bring Jake here” general manager Ben Cherington said. “He’s obviously a proven major league starter. He’s had a ton of success in his career. And I think if there’s one thing we wanted to do if we could pull it off it was to add a starting pitcher. As we looked at the next two months we’re in position to compete for a playoff spot and we just felt like adding a starting pitcher was probably the most important thing we could do to protect our chances to do that.”

The deal did not come without a cost. To secure Peavy the Red Sox parted with infielder Jose Iglesias a defensive wizard who turned third baseman Will Middlebrooks into a minor leaguer by hitting like Tony Gwynn for three months before slumping.

The Red Sox sent Iglesias to the Detroit Tigers receiving righty reliever Brayan Villareal in return. They also shipped three low-level prospects to the White Sox — right-handers J.B. Wendelken and Francelis Montas and infielder Cleuluis Rondon. The White Sox also received Tigers outfielder Avisail Garcia.

The Red Sox will assume the roughly $20 million and two years remaining on Peavy’s contract which includes a $15 million player option for 2015.

“It was important that if we were going to give up a long-term asset obviously in Iglesias a guy we have controlled long-term that we were getting someone we could control past this year” Cherington said. “When it came to the starting pitching market we were more focused on guys we could have past this year rather than just rentals.”

The 32-year-old Peavy is 8-4 with a 4.28 ERA for the White Sox this year with 76 strikeouts in 80 innings. His arrival means that last night’s starter and winner righty Brandon Workman will be moving to the bullpen which isn’t necessarily a bad thing.

Workman was outstanding last night. Backed by homers from Jacoby Ellsbury Dustin Pedroia and Jarrod Saltalamacchia Workman limited the Mariners to a run on six hits striking out nine walking one and lowering his ERA to 3.54. He saved his best for last too striking out the final two batters he faced to leave the bases loaded in the sixth inning.

“I couldn’t be more excited right now” Workman said. “Not only do I get my first big league win but it’s a big spot for a win for our team too so it’s a big spot all the way around.”