After just four minutes of the start of the evening session, the two players opted for a re-rack - and that set the tone for some sloppy and nervous snooker.
Jones notched a break of 50 before missing a red to the bottom left and with eight reds still on the table, Carter was able to score 49. Then it was The Captain's turn to miss a simple ball, the green to the middle pocket. Jones was able to pot that colour, but was unable to hold for the brown which saw a drawn-out exchange in what was increasingly looking like a crucial frame.
Carter potted the brown but missed an easy blue before Jones potted the blue and missed an even simpler pink into the middle pocket to gift the frame and a 10-7 lead to Carter.
Jones put that disappointment behind him to edge the next tight frame and was unlucky in the one following when he nudged the pink first in trying to break up another safety exchange by slamming into the pack. Carter took that frame and the next after Jones potted the white, moving within a frame of victory at 12-8.
Jones won the first two frames after the mid-session interval, racking up a break of 64 in the process - the first display of fluid snooker witnessed all evening.
Jones moved to within a frame of Carter after fortuitously knocking the cue ball over the top pocket, a predicament which Carter needed five attempts to escape from.
Carter was eventually able to seal victory with a patient and deliberate break of 71 to set up his semi-final showdown with Stephen Maguire.
Ali Carter retained a two-frame lead over Jamie Jones at 9-7 after the second session of their World Championship quarter-final in Sheffield.
Worlds debutant Jones traded the opening two frames of the morning session with 2008 finalist Carter before roaring to parity with century breaks of 138 and 132 in succession going into the mid-session interval.
But the Englishman replied to the 3-1 pre-break deficit by claiming three of the last four to bring the contest back to where it had started from the previous day.
Well-timed bursts of life snatch back his two-frame lead at 8-6 before a rousing 83 but Carter three clear, only for Jones to take an epic half-hour final frame on the final colour trail to keep his fairytale run at the Crucible alive.
32-year-old Carter, who sarcastically applauded second-round opponent Judd Trump after he landed some fortuitous snookers in their thrilling contest, fluked some of his own before going in-off while cutting the final brown into the middle and allowing the Welshman to prevent a four-frame chasm from opening in a match which threatens to go to the wire.
The two will conclude their last eight match from 7pm, with Stephen Maguire awaiting the winner on the one-table format in the semi-final.
Ali Carter moved into a 5-3 lead over Jamie Jones in the opening eight frames of their World Championship quarter-final in Sheffield.
Carter used runs of 47 and 58 to take the opening frame before tying Jones up in a host of snookers to double his lead.
But the Welshman fought back to level pegging heading into the intermission by edging a back-and-forth third frame before storming his way to the fourth with a superb 127 break.
32-year-old Carter, who finds himself embroiled in a war of words with Judd Trump after sending the Bristolian packing in a deciding-frame belter the previous day, moved ahead once more with a 77 before a run to 59 restored the two-frame edge.
And although Jones pulled one back with another impressive build – a 92 for 4-3 – Carter’s carefully-constructed 76 ensured he took an advantage into the conclusion of the last-eight tie on Wednesday.
Carter can move into the semi-finals with a session to spare if he is somehow able to win all eight frames tomorrow morning from 10am.