The Bexhill cueman will face world number 31 David Gilbert in the final round of the qualifiers on Tuesday for a place in the televised stages of the sport’s blue riband event.
Robertson, who qualified once before in 2011, held his nerve to edge out Anthony McGill 10-9 in the penultimate round of the qualifiers yesterday (Saturday) having overcome Liam Highfield 10-7 in the previous round on Thursday.
Against McGill, world number 52 Robertson shared the opening four frames - all of which were tight affairs - with Robertson making a top break of 56 in the opener. Robertson took the fifth to go 3-2 in front, but scored just 20 points in the next three as McGill knocked in breaks of 61, 92 and 78 to lead 5-3.
The first four frames of the second session later in the day were also shared. Robertson importantly came from 65 points behind to edge the opener, but lost the next despite opening the frame with a 52. Runs of 67 and 61 gave Robertson frame 11 only for McGill to win the 12th for a 7-5 lead.
Robertson eventually came through a long 13th frame and a 49 helped give him the 14th to level at 7-7. An 82 put McGill back in front only for Robertson to level once more at 8-8. McGill again edged ahead by winning frame 17 with a break of 60, but Robertson forced a decider by grabbing the next.
Former world amateur champion Robertson, 27, began the all-important final frame with a 39. McGill could manage only four when he returned to the table and Robertson knocked in a 64 to seal a hard-fought victory over the world number 43 from Scotland.
Against Highfield, Robertson held a narrow 5-4 advantage after the opening session, during which he fashioned breaks of 94, 80 and 73. Robertson took command by winning four of the first five frames in the second session, which he started with a run of 105, before closing out the match in frame 17.
Sixteen qualifiers will join 16 seeded players, including defending champion Ronnie O’Sullivan and St Leonards-based Mark Davis, in the televised stages, which will take place at The Crucible Theatre, Sheffield, from Saturday April 19 until Monday May 5.