The entire sports world mourns the loss of Pat Summitt, a giant in the game of basketball and one of the greatest to ever coach. Summitt died Tuesday at the age of 64 following a battle with early onset dementia, Alzheimer’s type. Summitt was diagnosed with the disease in 2011 and forced to retire at the age of 59, having won a record 1,098 games as the coach of the Tennessee Lady Vols. Summitt won eight national championships over the course of her storied 38-year coaching career and was inducted into the Naismith Memorial Basketball Hall of Fame in 2000.

The Post’s Sally Jenkins knew Summitt quite well, writing multiple columns about her friend, including several that are excerpted below. The two also collaborated on three books, the first being Summitt’s autobiography, “Reach for the Summit: The Definite Dozen System for Succeeding at Whatever You Do,” in 1999.

When Summitt’s illness was diagnosed late in the summer of 2011, Jenkins was there to assist her in making the news public.

Denial was followed by anger. For the first few weeks, Summitt would barely even discuss the subject. She told her doctors, “You don’t know me. You don’t know what I’m capable of.” Finally, Summitt realized she would have to accept the diagnosis. “I can’t change it,” she says. After a pause, she adds, “But I can try to do something about it.”

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In 2012, when Summitt retired from coaching, Jenkins was in Knoxville, Tenn., with her as she signed basketballs and contemplated her decision.

Leave it to Pat to make something good out of Alzheimer’s Disease, graceful, even. Which was pretty hard to do, with everybody staring at her for almost a year, wondering when she was going to crack or show telltale traces of illness. She has been under pressure from critics and friends alike to buckle under to the diagnosis and retire, to protect her so-called “dignity” and “legacy” by disappearing from public view. As usual, she has come up with an elegant solution to a difficult problem, and produced another victory.

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In 2013, the two friends joined forces to co-author a second book, this one called “Sum It Up: A Thousand and Ninety-Eight Victories, a Couple of Irrelevant Losses, and a Life in Perspective.” The Post printed an excerpt from the book, covering a portion of Summitt’s time as a basketball player at the University of Tennessee-Martin leading up to when Title IX was first introduced in Congress in 1972.

I had never been away from Henrietta, Tenn., before, except for one overnight trip with the 4-H Club. The Martin campus had fewer than 5,000 students and sat in a moderate-size town halfway between Nashville and Memphis, merely a two-hour drive from home. It was hardly cosmopolitan — but to me it felt as foreign as the other side of the globe, and I was scared to death of it. So scared that the very first weekend, I ran back to the farm. I found a ride to Henrietta and walked through the door of our farmhouse with my laundry under my arm.

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When covering college basketball, Jenkins would often turn to accomplishments by or lessons learned from her friend for perspective, such as when writing about Notre Dame playing in its fifth consecutive women’s NCAA Final Four in 2015.

Pat Summitt lost seven Final Fours before she won the first of her eight championships. For that matter, she coached 38 seasons — which means that 30 times, she went home feeling like a failure. … As my friend Summitt once so eloquently explained to me, “A lot of people are afraid of commitment because it means they’ll have to say, ‘That’s the best I can do.’ Too many people opt out, because they’re afraid of keeping score.”

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This past New Year’s, Jenkins sought to dedicate a poem to her friend and found the right one in Mary Karr’s “Loony Bin Basketball” despite it originally being dedicated to former Los Angeles Lakers and Chicago Bulls Coach Phil Jackson.

That was the sensation I had in stumbling on Karr’s dedication to Jackson — like invisible filament threads had formed a weird triangular connection. See, it was Jackson who taught Summitt the triangle offense, with which she won so many NCAA championships before she got Alzheimer’s disease. Pat taught the triangle to me when I was helping her write her memoirs. Karr is a famous memoirist. Karr, Jackson and Summitt, that’s a triangle.

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