Thomas Pieters becaume an international success last year when he teamed with Rory McIlroy at the 2016 Ryder Cup at Hazeltine and notched a 4-1-0 overall record for a European team that got soundly thumped by the Americans. He can become an international star on Sunday by going wire-to-wire at the WGC-Bridgestone Invitational for his first PGA Tour win.

Pieters, who has won three times on the European Tour, will have some pretty impressive company, though, as he goes for win No. 1 on United States soil after finishing in the top five at the Masters in April. 

He's tied with two-time major winner Zach Johnson at 9 under after 54 holes, and Hideki Matsuyama (7 under) and Rory McIlroy (6 under) are just behind them. But Pieters has been immense all week, never fully giving up a lead he took after Round 1 when he shot a 5-under 65.

Pieters leads the field in strokes gained on approach shots having gained nearly 10 on the rest of the field, which has hid the fact that he's nearly last in strokes gained around the green and has been mediocre with his putter.

On Saturday, he went on a tear and looked as if he might put the tournament away. He made birdie on four of his first five holes but faltered coming home with bogeys at Nos. 9, 13, 14 and 17. A birdie on the final hole on a 32-foot putt gave him a 4-under 66 and set him up for a Sunday close with the PGA Championship on deck next weekend.

Pieters' biggest competition might come from his Ryder Cup partner McIlroy who has been destroying shots off the tee all week. McIlroy told the Associated Press that he felt like his Saturday 68 could have (and maybe should have) been a 65 or 66.

McIlroy has gained five strokes on the rest of the field off the tee but lost shots on his approaches. His failure to turn that 68 into something special could portend well for a Sunday in which he'll likely need something like a 64 to win his second WGC-Bridgestone Invitational in as many tries.

And it would be immense for McIlroy to take that momentum into the PGA Championship at Quail Hollow next week where he has found so much success in the past. He turned the Bridgestone-PGA Championship double back in 2014 following his Open Championship win, and he could do so again this year.

But Pieters won't go down easily, and McIlroy has a lot of ground to make up. Three shots is one thing if you're trying to chase down, say, Scott Hend (who is also at the top of the leaderboard) and another thing if you're trying to run down somebody with the talent of Pieters and pedigree of Johnson.

Sunday should be a treat, though, with the best in the world duking it out for the year's final WGC event and a nice appetizer to the last major of the season next week. There have been plenty of fireworks over the first 54 holes -- mostly off the driver of McIlroy and the irons of Pieters -- and Round 4 should be much of the same.

Can McIlroy cut him short, or will Pieters capitalized on that Ryder Cup supremacy? We have 18 holes to find out. We have 18 holes to the beginning of one of the biggest weeks in recent major championship history.