Roger Federer had commentators searching for superlatives and Jeremy Chardy scratching his head after the "point of the day" at Indian Wells.
The world number one booked his passage into the final eight of the tournament courtesy of a 7-5 6-4 victory over the Frenchman.
Federer's brilliance was typified by a remarkable rally in the second set that saw him absolutely toy with his outclassed opponent.
Chardy showed tremendous defensive skills to keep the rally alive after Federer looked destined to win the sixth game of the second set comfortably.
The 36-year-old brought Chardy to the net with the deftest of drop shots, then lobbed the ball towards the baseline after the Frenchman scrambled his return over.
Incredibly, Chardy managed to retrieve the lob and send an eye-catching 'tweener' back Federer's way but the Swiss star was waiting at the net with an un-returnable drop shot.
"Oh point of the day," one commentator exclaimed.
"Tremendous stuff from both men who are thoroughly enjoying themselves out here."
The Swiss maestro will now play Chung Hyeon in the quarter-finals after the South Korean survived a late rally from Pablo Cuevas to hold on for a 6-1, 6-3 victory.
Uruguay's Cuevas fended off nine match points before eventually losing in the first-ever meeting between the pair.
Down a set and behind 5-0 in the second set, Cuevas miraculously saved seven match points to win the game.
He then served out the next game to cut Chung's lead to 5-2 and then broke the South Korean in the game after that.
Cuevas saved two more match points in the ninth game but his luck finally ran out.
World number 26 Chung faces Federer for the second time this year in the next round.
Chung made a Grand Slam breakthrough when he reached the semi-finals of the Australian Open in January but had to retire in his match with Federer because of a foot blister.
In other men's fourth round action, Croatia's Borna Coric blasted nine aces as he outlasted American Taylor Fritz 6-2, 6-7 (6/8), 6-4.
Coric improved to 10-3 on the season and 2-0 against Fritz. In 2016 they squared off at Roland Garros with Coric winning 6-3, 6-1, 6-3.
Coric, 21, needed two hours and 11 minutes to pull out the victory on the main stadium court against 20-year-old Fritz.
Unseeded Coric moves to the quarter-finals, where he will play South African seventh seed Kevin Anderson, who beat Spain's Pablo Carreno Busta 4-6 6-3 7-6.