Roger Federer and Venus Williams both had no problems progressing at Indian Wells overnight.
Federer stormed his way into his 11th semi-final at the BNP Paribas Open with a dominant win over Hyeon Chung.
The pair faced a re-match of their Australian Open semi-final - in which Chung had retired hurt - but the South Korean failed to improve his record against the world number one.
Federer, 36, toppled his 21-year-old opponent 7-5 6-1 after an hour and 23 minutes on court.
The match was more competitive than their meeting in Melbourne, however, with Chung rallying to come back from 3-0 down in the opening set to tie the scores.
But a focused Federer held his nerve, eventually breaking for another time to take the set.
The Swiss once again raced to a 3-0 lead in the second, and this time his opponent had no answers.
Federer's win ensures he will remain in the world rankings top spot for another two weeks, extending his record reign to 308 weeks.
He will now face another 21-year-old in the final four at Indian Wells - Borna Coric.
The Croatian came back from a break down in the third set to beat South Africa's Kevin Anderson 2-6 6-4 7-6 (7/3).
Having double-faulted to lose his serve at a crucial point in the deciding set, Coric could easily have crumbled.
But he fought on and broke straight back - despite the fact Anderson had only been broken twice in the tournament until that point.
Facing match point in the third-set tiebreak, Anderson lifted a forehand long, leaving Coric to progress to his maiden ATP World Tour Masters 1000 semi-final.
In the Women's tournament, Venus Williams secured her spot in the semi-finals for the first time since 2001.
The 37-year-old continued her run of fine form with a swift dismissal of Carla Suarez Navarro in the quarter-finals, winning 6-3 6-2 in a little over an hour.
Williams needed just one break - to go 4-2 up - in the opening set, before breaking again in the first game of the second.
Suarez Navarro fought hard to break straight back and level the scoreline, but a determined Williams broke two more times to claim the victory, even holding her nerve when faced with 0-40 on her serve at 3-2.
Her straight-sets victory means Williams has not yet dropped a set this tournament, where she also beat younger sister Serena in the third round.
Twenty-year-old Daria Kasatkina awaits in the semi-finals - the number 20 seed who has already dispatched of three grand slam champions in consecutive games this week.
The Russian defeated US Open winner Sloane Stephens in the third round and defending Australian Open champion Caroline Wozniacki in the fourth round, before stunning Angelique Kerber in the quarter-finals.
The 2011 US Open winner was brushed aside 6-0 6-2 after just 57 minutes on court.
An impressive backhand sealed an immediate break for Kasatkina, and a short backhand winner helped her move up a double break.
Her opponent, meanwhile, struggled, landing just 40% of first serves and winning only six points on her serve across the opening set.
Kerber managed to improve her statistics in the second, but failed to take advantage of opportunities.
She was broken twice in the second set, both conceded on costly backhand errors.
In the end, Kasatkina needed just one match point to clinch the win, and progress to the semi-finals.