When Marin Cilic catches fire, he does it in the same way he does most everything else. Quietly, with more light than heat, and almost no noise.

Wasn’t it just a few weeks ago that, in this same space, I lamented how hard it was to get a handle on this popular, diffident, six-foot-six 25-year old (think of another Juan Martin del Potro, but from Croatia)? I admitted that I couldn’t figure out why, with a game as big as the Balkans, he’s not a permanent resident of the Top 10 — in fact, I didn’t even understand the nature of his game, either in the stylistic or tactical sense.

Well, things are becoming a little clearer now. Cilic has emerged over the past two months as a potential force in 2014. Although he lost disappointing matches in Brisbane (Nishikori), Sydney (Istomin) and at the Australian Open (he dropped a painful five-set second rounder to Gilles Simon), he ignited at the smaller tournaments that followed.

Cilic won Zagreb (d. Haas) and made the final at Rotterdam (d. Murray in the quarterfinals, l. to Berdych in the final). In his two most recent matches, he beat John Isner and Kevin Anderson in back-to-back matches to win his 11th career title at Delray Beach. He’s on a roll going into the two spring North American Masters 1000 events.

What’s more impressive — after all, his recent good results came in small events — are some of his numbers, and how much Cilic seems to have benefited from his new coaching relationship with fellow Croatian and Wimbledon champ Goran Ivanisevic. Cilic has moved up from No. 37 to No. 25 in the ATP ranking. He’s visibly more confident and aggressive. He’s moving better. And through February he was the leading ace maker on the tour, with 247 in 22 matches.

Somehow, you just know Ivanisevic had something to do with all this — especially the last bit.  After all, the relatively young (42) and perhaps least heralded among the recent spate of “celebrity” coaches is the only man to break the 10,000 ace mark for his career, and he did it in fewer matches (766) than the No. 2 man on that list, Andy Roddick.

The odd element in play here is that, at least on the surface of it, Ivanisevic probably was the least likely candidate for coaching success among the new hires by top players. For most of his career he was a lovable flake — a verbal loose cannon who seemed incapable of answering a simple question with a simple, or at least straight, answer. Now here’s the flake, sounding and acting downright professorial.

“Over the past couple of years he (Marin) was not improving his game,” says Ivanisevic, who’s known Cilic for over a decade. “He was not getting anywhere. He was playing well, but not well enough to beat the top guys. He is a tall guy, so he needed to be more aggressive.”

Nobody knows better than Ivanisevic the degree to which you can lean on the serve, use it aggressively, and even actually transform your entire game by building it upon that rock. When you have an effective, commanding serve you plant nasty seeds of doubt in the mind of any opponent, great or small. Ivanisevic was famous for serving his way to four Wimbledon finals, and it was his serve that finally carried him to a title.

For years, Ivanisevic had professed that his deepest desire was to win the tournament he loved the most, Wimbledon. When it finally happened  in 2001, in the twilight of Ivanisevic’s  career, the feat immediately vaulted him into the lore and legend of the game. By then, Ivanisevic was injury-plagued, fading, and still charismatic but increasingly irrelevant. He got a wild card into that ‘01 Wimbledon (call it a “pity card” awarded for services rendered) and became—and remains—the only men's wild card entry ever to win a Grand Slam event.

All of this has a bearing on the present-day source of his notoriety in one significant way — among other things, Cilic probably has been one of the players most in need of daring to dream and finding the courage to embrace that dream, as Ivanisevic did at Wimbledon. And who better than Ivanisevic to teach Cilic that making the serve the foundation of his game may be the key to consistent success?

“At 198 centimetres, he had a shaky serve,” Ivanisevic recently told an ATP representative. “We have worked a lot. He is now hitting two aces per game and he is among the top two aces leaders on tour this season. He has never been up there before. He is getting a lot more free points on his serve, not necessarily aces, but he is getting short and easier balls to hit in response to returns. His second serve has always been good, but he has improved his first serve percentage.”

A big part of improving Cilic’s serve consisted of getting him to set up and hit it with less deliberation and a looser arm. In fact, Cilic needed to be a lot looser on the court, internally and externally, and becoming so has also made him a conspicuously better mover.

“Goran always relaxed when he hit his serve,” Cilic said in in Rotterdam. “We have simplified everything and it has made me more relaxed on the court.”

Cilic these days is sounding like a man who’s had his “Eureka!” moment. Perhaps that amorphous game has needed only an organizing principle — a reliance on the serve — in order to suddenly jell.

“We worked a lot on the first ball and volleying, which is where I needed to make the biggest improvement,” Cilic said. “I just wasn’t playing as offensively as I could over the past few years, meaning I wasn’t keeping points short or putting the other guy under extreme pressure.”

If there’s anything Ivanisevic knows about, it’s “extreme pressure.” He was a victim of it at Wimbledon, where the bludgeoning serve of Sampras frustrated him in two finals and a semi, but he also used it to good effect against almost everyone else, and — of course — in the course of his five-set (9-7 in the fifth) triumph over Pat Rafter on "People's Monday" in that enchanted ‘01 final.

Consider the wisdom gleaned therein imparted.