Gary Wilson reeled off five frames in succession to gain the upper hand against Ali Carter following the opening session of their World Championship quarter-final in Sheffield.
A total clearance of 135 had helped Carter race into a 3-0 lead and extended his streak of frames won to nine, the two-time Crucible runner-up having taken six in a row to beat Zhou Yuelong 13-9 on Monday.
However, Wilson stopped the rot with a break of 109 in the final frame before the mid-session interval and carried on where he left off after the break with contributions of 86, 134 and 55 to move 5-3 ahead.
The same quality was largely absent in the day's second quarter-final, with Kyren Wilson managing a highest break of just 46 in the first eight frames against David Gilbert.
Wilson, who had produced centuries in the last two frames to beat Barry Hawkins 13-11 in round two, somehow scrapped his way into a 4-3 lead before Gilbert, who had earlier made breaks of 68 and 60, saved the best until last with a 109 clearance to level at 4-4.
Both matches resume at 7pm on Tuesday before playing to a finish on Wednesday.
ga('create', 'UA-72310761-1', 'auto', {'name': 'pacontentapi'});
ga('pacontentapi.set', 'referrer', location.origin);
ga('pacontentapi.set', 'dimension1', 'By Phil Casey, Press Association Sport');
ga('pacontentapi.set', 'dimension2', 'd1273f8c-bdcc-45d2-bea8-319ff3ed3f6d');
ga('pacontentapi.set', 'dimension3', 'paservice:sport,paservice:sport:uk');
ga('pacontentapi.set', 'dimension6', 'story');
ga('pacontentapi.set', 'dimension7', 'composite');
ga('pacontentapi.set', 'dimension8', null);
ga('pacontentapi.set', 'dimension9', 'sport:other,sport:snooker');
ga('pacontentapi.send', 'pageview', { 'location': location.href, 'page': (location.pathname + location.search + location.hash), 'title': 'Gary Wilson battles back to claim advantage over Ali Carter'});