A maiden first-class century from rookie Surrey batsman Jason Roy proved in vain as their high-scoring Division Two clash with Glamorgan at The Oval ended in a draw.
After an over-cautious declaration, the visitors eventually set Surrey an unrealistic target of 395 off a minimum of 50 overs after reaching 259-4.
However, despite Roy's career-best 106 off 109 balls and an enterprising knock of 68 from Rory Hamilton-Brown as Surrey reached 194-1, the contest ended in a stalemate having never recovered from the loss of 71 overs on Thursday.
Resuming on 46-0, Glamorgan lost Will Bragg to Tim Linley early on, but then cantered through to the lunch interval without further loss, establishing a lead of 320.
Gareth Rees and Mike Powell added 185 in less than 34 overs, a new record for Glamorgan's second wicket against Surrey, before the former holed out to long-on after reaching a fine 126.
Roy, primarily a wicketkeeper but deployed as a declaration bowler, then picked up his maiden scalps in first-class cricket as he dismissed Ben Wright and Mark Wallace.
Roy and Hamilton-Brown evoked memories of great Brown Cap run-chases in raising a century stand in 15 overs as Roy raced to a 38-ball 50 with 10 fours.
But their momentum was checked when Hamilton-Brown was stumped off the bowling of Robert Croft and, while Roy went on to bring up a memorable ton, they resigned themselves to a draw and 10 points, while Glamorgan claimed seven.
Glamorgan's efforts to bat Surrey out of the match were thwarted by the weather on day three at The Oval
Less than 14 overs had been bowled before rain ended any chances of further play before lunch, leaving the visitors on 46 without loss in their second innings.
Resuming play with the hosts 179 runs adrift with four first innings wickets intact, Glamorgan wasted little time in mopping up the Surrey tail.
Seamer Chris Ashling ended the innings with career-best figures of 4-47 on his first start for Glamorgan.
Openers Gareth Rees and William Bragg had reached 16 and 24 respectively to take the visitors to 181 runs ahead with 10 wickets remaining when play was abandoned.
Alviro Petersen scored a double century as Glamorgan ended day two in a strong position against Surrey at the Oval.
In response to the visitors' 419, Surrey ended the day 179 runs adrift with four first innings wickets intact, having found themselves in trouble at 18-2 at one stage.
Jason Roy fell leg before to Chris Ashling, who struck again two overs later when Rory Hamilton-Brown was caught at the third attempt at third slip for 12.
But thanks to Mark Ramprakash - who passed 35,000 runs on his way to 67, Surrey recovered to 113-3 at tea, having also lost Zander de Bruyn, who became Alex Jones' maiden first-class scalp when he was caught and bowled off a leading edge.
Ramprakash added 90 in 24 overs in tandem with Steve Davies before driving loosely at Ashling to be bowled via an inside edge.
Earlier, Glamorgan lost their last six wickets for 64 runs to leave their card looking decidedly top-heavy. Tim Linley could have picked up six wickets in the first half hour, but two chances went to ground and another flew at a catchable height in-between second and third slip.
Alviro Petersen batted throughout the opening day for 178 not out as Glamorgan piled up 353-4 against Surrey at the Oval.
Having opted to bat first, the visiting skipper strapped on his pads and fully justified that decision with his first century since controversially being parachuted in to take charge of the Welsh county at the start of the season.
The South African hit 21 fours and a six during his 289-ball contribution and was well supported by Mike Powell during a 229-run stand for the third wicket.
Powell, however, missed out on a century of his own, bowled by Chris Jordan (1-70) for 99 in the evening session.