Nick Kyrgios stunned Rafael Nadal to set up a Mexican Open quarter-final against Stan Wawrinka, while Alexander Zverev also moved through.
Kyrgios incredibly eliminated two-time champion and top seed Nadal in the second round, saving three match points in a 3-6 7-6 (7-2) 7-6 (8-6) win on Wednesday.
The Australian came from 6-3 down in the final-set tie-break, reeling off five straight points to shock the 17-time grand slam champion.
Another huge test awaits in the last eight in Wawrinka, who beat American seventh seed Steve Johnson 7-6 (7-5) 6-4 at the ATP 500 event played on hard-courts.
German second seed Zverev recovered from a slow start to overcome veteran David Ferrer 7-6 (7-0) 6-1.
Zverev fought back after losing the first three games against Ferrer, the 36-year-old Spaniard who is retiring this year.
He will meet Alex de Minaur, who was given a walkover as Feliciano Lopez withdrew.
Of the eight seeds in action, four fell as Frances Tiafoe and Diego Schwartzman joined Nadal and Johnson in exiting.
Tiafoe lost to American countryman Mackenzie McDonald 6-7 (7-9) 7-5 6-3, while Schwartzman went down to Cameron Norrie 7-6 (7-5) 4-6 6-3.
That winning duo will meet in a quarter-final, while John Isner will take on John Millman.
Isner served 19 aces in a 6-4 6-4 win over Sam Querrey and Millman was untroubled by Peter Gojowczyk, easing to a 6-0 6-2 victory.
At the Brasil Open in Sao Paulo, three-time champion Pablo Cuevas made a first-round exit, while Guido Pella and Leonardo Mayer reached the quarter-finals.