Britain's Andy Murray stormed into the world's top 100 with a hard-fought win over Swedish fifth seed Robin Soderling at the Thailand Open on Thursday.
The pair traded breaks twice in the first set before Murray dominated the tiebreak 7-3 to clinch the opener 7-6.
The 18-year-old Scot then received treatment for a headache before trading breaks again and winning another tense tiebreak 7-5 to win the second set 7-6.
Murray now meets US third seed Robby Ginepri for a place in the semi-finals.
The Dunblane teenager becomes only the fourth British male to achieve a ranking in double figures since 1995.
The win also guarantees Murray automatic entry to January's Australian Open and marks another milestone in a meteoric year for the feisty youngster.
"It's a pretty big deal for me, getting to the top 100 when I'm 18," said Murray.
"I said at the start of the year that's my goal. After the first couple of months a lot of people told me I should have kept quiet. But I'm pretty happy with myself now.
"I wasn't feeling that great towards the end of the first set.
"But I took a timeout and got some medication from the doctor. I had a really sore head. I don't know why.
"But I thought I played a pretty clever match. I used my slice pretty well and I didn't give him so much pace which I think he likes. I returned well in the first set and when I had to in the second.
"I thought I could have served better and maybe attacked a little bit more, but it was a pretty big match for me and I'm just happy to come through."
Murray hit the headlines for the first time in August 2004 when he won the US Open boy's singles title at Flushing Meadows.
He went on to make his ATP debut in April, when he was ranked just 397th, before a stunning third-round run at Wimbledon led to many hailing him as the successor to long-time British number one Tim Henman.
In the wake of Wimbledon, Mark Petchey resigned his post as head of men's national training at the Lawn Tennis Association to coach Murray.
And two Challenger titles - in Santa Cruz and New York state - as well as a respectable US Open debut have since proved Petchey's charge has the potential to match the hype.
But looking ahead to his clash with US Open semi-finalist Ginepri, Murray admitted the hard work is only just beginning.
"He's played really well the last couple of months and he's got a lot of experience, so it's going to be pretty difficult," the Brit said.
Federer kept his emotions in check against Denis Gremelmayr
"I'm not expected to win, and I'll have to serve well to stay with him."
World number one and top seed Roger Federer also reached the quarter-finals in Bangkok on Thursday, breezing past Germany's Denis Gremelmayr 6-3 6-2.
The Swiss was back in cruise control as he notched up his 74th win of 2005 after uncharacteristically losing his cool as he struggled to get past Brazilian Marcos Daniel on Wednesday.
"A different day, a different opponent. It changes things," said Federer, who now faces Luxembourg's Gilles Muller.
Muller upset eighth seed Luis Horna 7-6 (7-4) 6-7 (4-7) 3-6.
Lleyton Hewitt survived four match points to edge past Justin Gimelstob 6-4 5-7 7-6.
"When he keeps coming at you like that he's a tough player to play against," a said a relieved Hewitt, who will next meet local favourite Paradorn Srichaphan.