For much of his career, John Isner’s lasting highlight on the grass courts of Wimbledon was one he would rather forget – his 11-hour, five-minute epic against Nicolas Mahut in 2010.

Though he eventually grew to appreciate his record-breaking victory as the media storm surrounding it petered out, the 33-year-old was always eager to add a different sort of highlight to his Wimbledon resume – one that included success in the famed event’s second week.

Entering his 10th Wimbledon this year, Isner had never advanced beyond the third round, a puzzling statistic, given the server-friendly courts at the All England Club. But as the 6-foot-10 bomber explained, he struggled throughout his career with the low, grass-court bounce that kept the ball well below his strike zone and the slick surface that made it hard for his big frame to catch up with the ball.

Isner would tower over even lanky, big-serving Wimbledon legends, like Pete Sampras (6-foot-1) and Goran Ivanisevic (6-foot-4), and it seems grass courts accentuated the fact that his height could be both his greatest strength and his greatest weakness.

In each of his last three Wimbledon appearances, Isner has gone out in five agonizing sets, including a pair of third-round losses to Marin Cilic (2015) and Jo-Wilfried Tsonga (2016) that ended 12-10 and 19-17, respectively, in the final set.

Ruben Bemelmans almost furthered that trend this year, as he held two match points against Isner in the fifth set of their second-round matchup. But from 15-40 down, the American fired four aces to get out of trouble before immediately breaking the Belgian and serving out the match, 7-5, in the decider.

Now, having reached his first Wimbledon semifinal – eclipsing his previous best major performance, a quarterfinal run at 2011 US Open – the Greensboro, N.C., native’s long-awaited Wimbledon run comes in the midst of what is shaping up to be the best season of his 12-year career.

“I do believe that, at 33, I’m playing my best tennis,” Isner told USOpen.org after his opening-round win, a straight-sets result over Germany’s Yannick Maden. “I think [winning my first Masters title in] Miami was indicative of that. So as long as I'm feeling healthy and strong and eager to get out there, you know, I think I can do well here.”

He followed up that early-April Miami title, earned with a three-set final victory over world No. 3 Alexander Zverev, with a fourth-round run at the French Open, matching his career-best performance on the red clay.

Entering Wimbledon as the ATP’s top-ranked American and the world No. 10, Isner was just one spot below his career-high ranking. He has been ranked No. 9 on three occasions, in 2012, 2014 and earlier in 2018.

If there is a silver lining to his prior Wimbledon struggles, it is that his second-round performance in 2017 left him with just 45 ATP ranking points to defend at this year’s event.

Now, having finally conquered his Wimbledon hoodoo, Isner's quarterfinal victory over Milos Raonic guarantees him a new career-high ranking of No. 8 when the updated ATP rankings are released.

The Dallas resident's Wednesday victory secured him 750 points as a semifinalist, enough to vault him above current No. 8 Dominic Thiem, a first-round victim on the London grass. Looking even further ahead, a Wimbledon title would see him rise to No. 5.

“I certainly would love to get to No. 8,” Isner said earlier in the tournament. “This is my third trip inside the Top 10. Never could get to the Top 8.”

Mission accomplished.

Looking at the big picture, he has his sights set on finishing the year in the Top 10, something he has not done in his career. In the ATP Race to London, he is currently No. 8, with the American hard-court swing and the US Open still to come.

“I’m in a very special position now,” he said, “and I want to make the most of it.”

Of course, Isner will take it one match at a time. For now, the focus remains on the task at hand and on the grass courts that are particularly firm this year and, according to Isner, playing more like his preferred hard courts than in the past as a lengthy London heat wave takes its toll on the lawns.  

Surely that has something to do with his magical run, but take no credit away from the hard work the veteran American has put in away from the spotlight that has allowed him to evolve his game and peak at age 33.

The former Georgia Bulldog opted not to play any grass-court tournaments in the buildup to Wimbledon this year, making the calculated decision to put in more time on the practice courts while keeping his body fresh for the main event. As he continues to compete deep into the second week, that decision may continue to reap rewards. His efficiency over the past week has helped him keep that extra energy in reserve, as he has dropped just one set in the tournament outside of his second-round scare.

With 161 aces through five matches thus far, Isner has yet to be broken in the tournament, saving all seven break points he has faced. In this form, no one in the field would envy lining up against him.

Kevin Anderson, his semifinal opponent, will enter Friday's showdown on the heels of a four hour, 14 minute five-setter against Roger Federer. The South African battled back from two sets down to pull off the upset, 13-11, in the fifth.

He now faces a tall task – in more ways than one – as he attempts to recover before battling Isner on Centre Court.