This March, in a match against Ivo Karlovic in Indian Wells, Jack Sock bounced an overhead out of court and into the stands. A fan picked the ball up and quickly thew it back. Quickly, and with comical precision: His toss hit Karlovic, who hadn't turned around to see where the ball had gone, squarely in the back of the head.

The crowd went silent—how would the big Croat react after such an offense? He had been playing poorly, and the California fans had already spent a set and a half rooting for Sock, a young American. Would this be the final straw? A longtime master of deadpan humor, Karlovic knew exactly how to handle the situation. After the ball bounced off his noggin, he stopped in his tracks, stared straight ahead, and, as the audience’s nervous laughter began to grow, slowly turned his 6’10” frame to face his new enemy. Without cracking a smile, Karlovic asked Sock for a ball. When he got it, he lifted it in the air with one hand and cocked his racquet with the other, as if he were about to give the spectator a taste of his own medicine, times 100. Karlovic, smiling slightly now, held the pose for a millisecond—long enough for it to cross my mind that he might actually smash the ball—before finally dropping his hands and exchanging a laugh with the fan. The crowd loved it, so much so that many of them transferred their allegiance to Karlovic, who came back to win in three sets.

A lot of tennis fans have been transferring their allegiances toward the 34-year-old veteran these days. This weekend, belying his age and his ranking of 155, Karlovic won his first tournament in five years, in Bogota. That would be remarkable in itself, but what makes the story just short of miraculous is that as of this spring, Karlovic wasn’t sure he would ever swing a racquet again. In April, at a Florida Challenger event, he was diagnosed with viral meningoencephalitis, a disease that causes the brain to swell and leads to seizures. As Karlovic said earlier this month, after his episode he spent four days in an intensive care unit, unable to remember his name.

By July, he was back on tour, and in the quarterfinals at Newport. But while Karlovic’s body had recovered, the mind had a little ways to go to accept it. In that Newport quarterfinal, against John Isner, Karlovic staggered dizzily during a rally before walking to the sideline. There he sat staring at the grass, seemingly unsure of what was happening to him. As trainers and doctors gathered around him, all you could see in his eyes was fear. Again, though, Karlovic recovered quickly and finished the match.

For me, those few seconds on the sideline brought home the danger of Karlovic’s situation, and immediately made me root for him in a way I never had in the past. For better or worse, that’s the way it works in sports, and in tennis: It’s easier to appreciate athletes when you sympathize with them, when misfortune hits or the aging process begins to take its toll. Monica Seles was never as beloved before she was stabbed as she was afterward. Jimmy Connors was detested by New Yorkers at the U.S. Open when he was 22; by the time he was 39, he had become an adopted son of the city. Something similar has happened to Venus Williams as age and illness have taken their toll on her. There’s no reason to be cynical or embarrassed about these shifts in perspective. Sympathy for a player allows us to see more clearly what was always in that person, waiting to be liked.

In the past, Karlovic was known as the slightly sinister Dr. Ivo, a towering, glowering man with an unbreakable serve, someone you never wanted to see near your favorite player in a draw. As Rafael Nadal said after he barely escaped from the jaws of the ace machine a couple of years ago, Karlovic turns tennis into a “lottery.”

There is always something of the novelty act to a Karlovic match. With his inability to break or be broken, what he ends up playing isn’t tennis in the conventional sense. Unfortunately, while the result may be novel, it’s not wildly entertaining. Andy Roddick echoed the thoughts of many fans when he played Karlovic in Washington, D.C., a few years ago. Sometime in the middle of the first set, after each player had made his way through a few routine holds, Roddick could be heard muttering, “Let’s just get to the tiebreaker.”

There has always been something of the misfit to Karlovic. Instead of playing the obvious sport for a man his height, basketball, he found his own way to a tennis court. Early in his career, he had trouble with a stammer. More limiting was his game itself, which consisted of his supersonic serve—he's the only player I've seen hit completely flat aces out wide in the deuce court—and little else. But against the odds, and with a lot of work, Karlovic rounded out his game and turned what looked like a one-shot act into a 13-year pro career that’s still going strong. In 2004, Karlovic upset top seed Lleyton Hewitt in the first round at Wimbledon. In 2008, he reached a career high of No. 14 and beat Roger Federer in Cincinnati. And this weekend he won his fifth career title and re-entered the Top 100.

If Karlovic, who has a daughter with his wife, Alsi, a native of Jamaica, draws more fans going forward, they may discover what the crowd in Indian Wells found out in March: He has a sense of humor. His followers on Twitter already know this. While his Tweets can trend toward the coarse and scatological, few other athletes are as acerbically self-deprecating:

“I overheard a lady walking behind,” Karlovic Tweeted earlier this month, “asking her friend, ‘Is that Milos?’ I said I know I look young, but I don’t think I look Canadian.”

A few weeks earlier he posed this Zen-like riddle:

“If I’m driving a car and nobody’s there to witness me jamming to Bieber’s song on radio, was it worth paying for tinted windows?”

Recently, though, a different type of Tweet has crept into Karlovic’s repertoire. Sarcasm has been replaced by a joyful appreciation for life:

“Felt so good to play a match again,” he wrote during Newport. “Win or lose, don’t matter. Just two months ago, I thought it was over.”

This past Sunday, Ivo felt even better:

“Omg what a feeling,” Karlovic exulted after winning in Bogota. “Life is good!”

Nothing more needed to be said; we know where Dr. Ivo is coming from these days. We may, as we watch him play, still urge him “just to get to the tiebreaker,” but more of us will be rooting for him when he gets there.