Judd Trump took a 5-3 lead over four-time champion John Higgins after the first session of their World Championship quarter-final at the Crucible.
Trump, who lost to Higgins in the 2011 final, reeled off breaks of 58, 100 and 71 in successive frames to take a 4-1 lead.
Higgins responded with a run of 74 to take the sixth frame and also claimed the seventh, but Trump ended the session with a break of 77 to ensure an overnight lead in the best-of-25 clash.
Barry Hawkins claimed the upper hand after a hard-fought opening session of his quarter-final against Ding Junhui in the Betfred World Championship.
Hawkins compiled breaks of 64, 82, 50 and 60 to take a 5-3 lead in the best-of-25 contest at the Crucible in Sheffield, while Mark Allen and Kyren Wilson ended the session locked at 4-4.
Making his sixth consecutive appearance in the last eight, Hawkins settled quicker than his opponent and led 3-1 at the mid-session interval before Ding reduced the gap with a fluent 76.
Hawkins re-established a two-frame cushion by winning the next and, although Ding again hit back with the help of a break of 67, Hawkins enjoyed a useful slice of luck in the eighth frame.
The left-hander miscued when attempting a plant, but the red still found the middle pocket and a break of 60 eventually proved enough to clinch a deserved 5-3 advantage.
On the other table, Wilson recovered from losing the first frame to compile breaks of 52, 125, 90 and 83, but was unable to shake off a determined Allen in a repeat of their Masters final.
Allen, who beat Wilson 10-7 at Alexandra Palace in January, won the fourth frame with a superb long pot on the black and claimed the final frame of the session with a break of 78.