Over the first seven days of the 2018 World TeamTennis season presented by GEICO, the Springfield Lasers lost twice as many matches as they won.

Two weeks later, they became league champions.

For the first time in the franchise's 23-year history, the Lasers captured the King Trophy to close out the 2018 World TeamTennis  presented by GEICO season by defeating the Philadelphia Freedoms, 19-18, in Sunday's final on the campus of Drexel University.

After starting the season 2-5, the Lasers won six of their last seven matches in the regular season to pull off the improbable and reach the season's showpiece match.

They needed to pull off another stunner on Sunday, as they took an early lead but needed to rally late.

After losing the first two sets in men's doubles and women's doubles, the top-seeded Freedoms, who went 12-2 in the regular season, looked on course to raise their first King Trophy in 12 years as they engineered a comeback in the middle sets. The league's Female MVP, Philadelphia's Taylor Townsend, capped a perfect season in women's singles (13-0) with a 5-2 win over Vania King in the fourth set to give the Freedoms their first lead since the first set.

WATCH —Highlights from the Lasers' win over the Freedoms in the Mylan WTT final:


In the end, it came down to the league's two best men's singles players, and it was the Lasers' 18-year-old Miomir Kecmanovic who defeated WTT Male Rookie of the Year Kevin King in the final set, 5-3, to seal the upset victory.

"It was definitely tough in the end," Kecmanovic said in the on-court trophy presentation. "We were behind a lot, but I tried to keep calm. I tried to stay focused throughout the whole match, and thankfully, it paid off in the end."

The rookie won four straight games to seal the final set, as King first saved three break points in the opening game and jumped out to a 3-1 lead.

Springfield previously reached the WTT Finals on five occasions, in 1999, 2001, 2009, 2013 and 2014, but came up second-best each time.

Twelfth-year head coach John-Laffnie de Jager dedicated the win to team founder Harry Cooper, who passed away earlier this year.

"This is for the people of Springfield and Mr. Cooper. I talk about 'champion people' in life and the people in this franchise are all champion people," he said.

"To win for the people of Springfield means a lot. They have been so good to us and I'm so glad we can bring the King Trophy back to them."