The 28-year-old Englishman shot a seven-under-par 63 on the Tour Course at the PGA Catalunya Resort to springboard into a share of the lead alongside Sweden's Jens Dantorp.
The top 70 after Wednesday's fourth round will advance to the final 36 holes on Thursday and Friday, following which the top 25 will win a spot on next year's European Tour.
Morrison began the day seven shots off the lead but got to the turn in 31 and further birdies at 10 and 11 had him closing in on the leaders.
A bogey at the 12th stalled his progress but further birdies at 16 and 18 ensured he would have a share of the lead going into Wednesday.
Dantorp's round was less spectacular as he fired a second consecutive 68 to maintain his consistent form with just four shots dropped in his opening three rounds.
Paraguay's Fabrizio Zanotti and Argentina's Estanislao Goya sit a further shot back ahead of a large group on eight under including England's Simon Wakefield and Gary Lockerbie and Scot Jack Doherty.
American John Hahn looked like maintaining his overnight lead as he reached 12 under after 10 holes but three bogeys and a closing double sent him tumbling to a three-over 73.
That left him in the group at seven under alongside Scotland's Alastair Forsyth and English duo Richard Finch and Daniel Brooks.
Par is currently good enough to get players into the final two days on the Stadium Course and among those struggling to make it could be 2011 Czech Open winner Oliver Fisher, who sits two over, and former Ryder Cup star Phillip Price, a further shot back.
Three three-time European Tour winners have struggled: Peter Hedblom reached five over, Nick Dougherty six over and Johan Edfors seven over.