When Lil Wayne first came into my life during the late 90s, as I whiled away my high school years spending untold hours watching hip-hop music videos on The Box, I scarcely could have imagined the scrawny teenager from the Hot Boys would in a decade’s time become the biggest rapper on the planet.

Of course that’s exactly what happened. The baby-faced, froggy-voiced New Orleans prodigy became not only one of music’s towering stars as a solo performer – ultimately surpassing Elvis Presley for most songs by a male artist to chart on the Billboard Hot 100 with a staggering 109 entries – but an indelible figure in American public life: showered with awards, name-checked by Barack Obama and Bill Clinton, sought after for collaborations by everyone from Madonna to Kanye to Paris Hilton.

By the time he was sentenced to a one-year bit on Rikers Island for a weapons charge in 2010 – the subject of a long-awaited memoir set for an 11 October release – Weezy was at the peak of his powers, the heady late-aughts run of Da Drought 3, Tha Carter III and No Ceilings still fresh in the public ear.

At the time I was a twentysomething worker bee at Sports Illustrated and always on the lookout for fresh angles at the intersection of sports and culture – anything unexpected or fun to retain the readers we’d been hemorrhaging. So when the Young Money team launched WeezyThanxYou.com, a website that listed a mailing address for their incarcerated paterfamilias on Rikers and solicited fan mail, I thought I’d take a flier and ask him to write for us. And what better topic than a passion I knew was near and dear to his heart: professional tennis.

Lil Wayne’s letter to the author from Rikers Island in August 2010. Photograph: Courtesy of Bryan Armen Graham

The slim overlap on the Venn diagram between southern hip-hop lovers and tennis wonks that I call home had long been aware of Wayne’s love for the sport. He’d mentioned it in interviews through the years and even sampled Elena Dementieva’s grunt on 2006’s Da Dedication 2. With the US Open looming on the calendar, I thought it would be fascinating to get his musings on the tournament and the sport in general.

I posted three sheets of company stationery, a self-addressed stamped envelope and a short letter that introduced myself and made a simple request: write about tennis for Sports Illustrated.

That was in June, more than two months before the Open. I’d be lying if I said I expected a response. Weeks passed until I’d completely forgotten about sending it. But when I checked my mailbox on the day of the draw, I saw a SI-branded envelope with my handwriting across the front. My chest tightened. I carried it to my desk and carefully peeled it open, not knowing what to expect.

His response expressed his love for the stars of his childhood (Andre Agassi) and the present (Maria Sharapova). He trafficked in statistics and weighed his predictions against injury prognoses: Rafael Nadal would overcome his knee tendonitis, while Serena Williams’ right foot injury would open the door for Kim Clijsters. The prose was measured, the penmanship immaculate.

While most of my editors had no idea who Lil Wayne was when I shared the news in morning conference, the smarter ones were keen enough to know from our interns’ giddy reactions what it meant. We ran it online and in the front of the book. People magazine caught wind from a few floors below in the Time-Life Building and asked to run it in their forthcoming issue. Dozens of blogs in the music, sports and culture spaces picked it up.

And Wayne’s insight proved prescient. He correctly predicted the eventual winners for both the men (Nadal) and the women (Clijsters), a feat matched by none of the magazine’s six experts, present company included.

The whole thing earned me a bit of notoriety in the building, for which I was grateful. Before the end of the day I posted Wayne a thank-you package including every magazine from the last six months (leaving out the Swimsuit issue, lest I run afoul of the prison’s no-porn policy). I received a kind call from Wayne’s manager Cortez Bryant thanking us for including him.

Wayne was released a few months later and I attempted to keep up our correspondence. When he returned to New York to headline Hot 97 Summer Jam on the same day as the 2011 French Open final between Federer and Nadal, I’d heard he was staying at a hotel in Manhattan and reached out about watching the match with him. It never happened. After a while the connection frayed, though I do reserve hope we can reconnect over a match one day. Maybe at Wimbledon.

Over time it’s become my Lincoln Letter, a sentimental token of an erstwhile era that rates among my most treasured personal effects. But unlike Major Marquis Warren’s clever forgery, this correspondence was authentic. Short-lived but real all the same.