In addition, they became the first recipients of the Irvin Iffla Shield, a trophy which will be up for grabs each time these sides meet. The prize has been raised in honour of the great West Indian all-rounder, who captained both Stirling and Ayr after settling in Scotland during the 1950s.
Iffla died earlier this year and it was fitting that Keith Graham, a man who has also skippered these two sides, was a guest of honour to witness the unveiling of a memorial bench before Ayr completed an 83-run win.
Graham said: "Irvin was a great man and a great cricketer and this trophy is a fitting way to keep his memory alive. He was a straight-talking guy that you didn't mess with and I got on with him extremely well.
"I think there was an appreciation of mutual cricketing knowledge. We shared some great partnerships with bat and ball.
"Irvin was also very generous. Often in games that didn't matter too much he would get a young player out lbw but not appeal because he wanted to give the youngster another chance."
On the day it was Craig Thyssen, Ayr's South African professional, who made the difference. He stroked a superb 97, supported by Andi McElnea's 38 as the visitors posted 212. Stirling were dismissed for 128.
Elsewhere, the lead changed hands as Dumfries suffered defeat for the first time, at the hands of Uddingston, while West of Scotland took advantage by beating Greenock.
Having restricted Uddingston to 189-8 at Nunholm, Dumfries, who had chased scores in excess of 230 in their two previous matches, may have fancied reaching their revised target of 182 in 40 overs. However, Calum MacLeod claimed 4-33 as the home side were restricted to 157-7.
West are the new leaders after a brilliant eight-over spell by John Blain turned their game with Greenock at Hamilton Crescent.
The visitors were holding their own before former Scotland bowler Blain entered the attack to claim 3-8. If he was fortunate to get visiting pro Mpho Sekhoto caught behind when the ball appeared to strike the South African's pad, there was no argument about the deliveries which accounted for Chris Hempsey and Sailesh Prabhu for 47.
After a rain interruption Greenock closed on 135-8 before West easily reached their revised target of 164 with seven wickets in hand. Teenager Andrew Umeed top-scored with 66.
Rain was the winner at Titwood where just 3.4 overs were possible in the clash between Clydesdale and Drumpellier.
Carlton, who returned to winning ways in the Eastern Premier Division, will be without their Scotland all-rounder Preston Mommsen for several weeks. However, captain Fraser Watts is delighted that his team-mate is getting the chance to play at a higher level. Mommsen has been called up by Leicestershire for the defence of their T20 county crown after impressing in a couple of four-day championship matches.
Watts said: "This is great news for Preston and it reflects well on the club and Scottish cricket in general. It is a big opportunity for him and I am sure he will perform to a high standard."
Watts hailed the accuracy of his seam attack in the wake of the demolition job on Aberdeenshire at Grange Loan. After Carlton were dismissed for just 138, their bowlers rose to the challenge to skittle the Mannofield men for a dismal 64, with Omar Ahmad claiming five for 13.
The captain added: "It was a green track and I wasn't too worried about our total in the circumstances. I knew that if the seamers put the ball on the right spot we would have a pretty good chance."
Arbroath appear to have contracted second season syndrome and lost again, to Grange at Lochlands. Grange reached the target of 178 with seven wickets and eight overs to spare. Only Calvin Burnett (36) was able to put up any meaningful resistance to the visiting attack, for whom veteran Stuey Davidson starred with three for 28.
Four of Grange's top five passed the 30 mark. Gregor Maiden (43) and Neil McCallum (31) laid the foundations before Smudger Smith (35 not out) and Stuart Moffat (33 not out) finished the job.
Calvin Burnett took all three Grange wickets for 28.
To add another disappointing weekend for the Tayside clubs, Forfarshire succumbed to Heriot's at Broughty Ferry.
In spite of a five-wicket haul for Dale Sweeney, the Edinburgh side made 228 for eight, thanks mainly to 57 apiece from David Ross and Qasim Ashraf.
Brendan Ford (53), Aman Bailwal (30) and captain Craig Wallace (30) gave the hosts a chance, but the lower order were unable to maintain the momentum when it mattered and Forfarshire were bundled out for 193.
Stuart Chalmers was in prime form for Watsonians, as they maintained their 100 per cent record with an emphatic victory over the other form team in the division, Stoneywood-Dyce at Peoples Park.
The inspirational captain hit 88 of his side's 214-6, while namesake Ewan made 64 and Craig Wright added 40. Chalmers then claimed three wickets, a feat matched by Mike Legget as Stoneywood were shot out for 94.
In the first division, Ferguslie bowler Jamey Carruthers is convinced the Paisley club are on the way back to the top flight. The youngster took three cheap wickets as Ferguslie beat East Kilbride but his ambitions for the Meikleriggs goes beyond even this season's title as he targeted a return to their former status as SNCL Premier contenders.
Carruthers said: "We are playing pretty well just now. It was good to get the benefit of the result, however we made it harder than it should have been.
"The spirit in the club has improved over the past couple of years and we just need to keep it up."
Carruthers took three cheap wickets to help curb East Kilbride to 150 for nine in 46 overs.
That left Ferguslie with an amended target of 146, which they managed to overhaul in the 42nd over, but with only two men to spare.
David Stafford (38) and Michael English (35) proved the main men with the bat.
Elsewhere in the First Division West zone, old campaigner Imran Adrees produced a devastating spell of seven for 17 to propel Renfrew to victory over Prestwick at King George V Park.
Kelburne shrugged off the challenge of Stenhousemuir, while the Weirs v Poloc tussle was abandoned due to rain.
In the East section, the woes of Edinburgh Accies deepened as they were brushed aside by Falkland at Newfield.
West Lothian continued to climb the table thanks to their eight-wicket win against Freuchie at Boghall.