Some excellent snooker from both Kyren Wilson and Ding Junhui helped them knock out Mark Allen and Judd Trump respectively, as Mark Selby remains the only top ten player to reach the last eight thus far.
The two last-16 encounters were full of drama, and have really opened up the draw at the World Championships.
Wilson matches Allen frame for frame to win 13-9
Kyren Wilson found himself firmly in the driving seat when he led 7-1 over Mark Allen after a riveting first session of snooker, but the man from Northern Ireland hit back with an electric start to Sunday evening's second session.
Allen produced breaks of 122, 103, 60 and 66 to win four consecutive frames and put himself right back into contention. Yet the world number seven let his form dip, as Wilson won the last four frames of the session to restore his lead of six, with the final two frames of the session decided by less than ten points.
The score left young starlet Wilson requiring just two frames in Monday's afternoon session to earn a quarter-final spot. Once more his opponent came out firing to take the first two frames, but yet again Wilson matched Allen as he won two consecutive frames of his own to ease to a 13-9 victory. The result leaves Wilson with a last eight tie against world number one Mark Selby which begins on Tuesday.
Ding continues to build momentum
World number five Judd Trump found himself in trouble against Ding Junhui as he was left 6-2 behind after the first session dominated by a Twitter incident between Trump and Dominic Dale, with the former calling Dale "clueless". A nervy second session ensued as both players only made one half century each and the pair shared eight frames between them to leave the tie 10-6.
A higher quality session played out on Monday afternoon as Ding and Trump both made half century breaks in the opening frame, with the latter prevailing by five points. Yet Ding hit back with two frames of his own helped by breaks of 72 and 91 to take the lead to 12-7, meaning Trump needed to win six frames on the bounce for victory.
Trump threatened a comeback as he made breaks of 61, 56 and 88, before Ding showed his class to eventually prevail 13-10. He sets up a final eight tie against Mark Williams commencing on Tuesday.