Luke Donald maintained his impressive run of form at the WGC-Accenture World Match Play with a 3&2 victory over Italian Matteo Manassero.
Donald has yet to trail all week and had too much matchplay nous for the 17-year-old, as he secured his quarter-final berth in Arizona.
The teenager is the youngest player ever to compete in the event and was on a real high after knocking out Steve Stricker and Charl Schwartzel in the first two rounds.
But the 2009 British amateur champion, already a European Tour winner in his nine-month-old professional career, found Ryder Cup star Donald a much tougher proposition.
Manassero could not match the 33-year-old's birdies at the first and fourth, bogeyed the next and then saw his opponent fire in his approach to three feet at the seventh.
Ninth seed Donald did lose the long eighth, but his response was immediate - a 20-footer for another birdie at the next and then a par on the 10th to go five up despite driving into a greenside bunker.
Manassero chipped in for eagle at the 13th and birdied the 15th to take that as well, but Donald clinched his first last eight spot in seven attempts on the next.
If Donald can go all the way and end five years without a win in America, he will move to third in the world behind Lee Westwood and Martin Kaymer - with Northern Ireland's Graeme McDowell fourth.
But the US Open champion has still to make the quarter-finals here, after going out to Korean YE Yang.
McDowell had come from behind in his first two games and threatened to do the same when he took the ninth and 10th to level.
But Yang, the player who beat Tiger Woods head-to-head in the 2009 USPGA Championship, went away from him again and sealed victory with a chip-in birdie at the 16th.
Donald will play American Ryan Moore in Saturday morning's quarter-finals. Nick Watney birdied the 17th and 18th to draw level with his fellow American, but Moore won the match with a 12-ffot birdie putt at the first extra hole.
Jimenez wins 8&6
Biggest win of the day went to 47-year-old Spanish veteran Miguel Angel Jimenez, who crushed Ben Crane 8&6 a day after the American had seen off Rory McIlroy 8&7.
Jimenez, trying to become the oldest winner of the title by 10 years, won the opening four holes, three of them with birdies, and never looked back.
Jimenez will play Kaymer on Saturday after the German USPGA champion saw off American Hunter Mahan 2&1.
Because of a bad weather forecast for Sunday morning - with a possibility of snow - the schedule for the event has been changed so both the quarter-finals and semi-finals will now be played on Saturday.
The quarter-finals will start at 7.10am local time (1410 GMT) and the semis at 11.45am (1845 GMT). The final, 18 holes for the first time this year, will then tee off at 12.15pm on Sunday (1915 GMT) if conditions permit.