The 33-year-old is up to 108th on the money-list after earning £59,500 for claiming a share of seventh spot behind home winner Francesco Molinari in the Italian Open at Monza.
Jamieson, who was without a top 10 this season until he tied for 10th in the KLM Open in Holland the previous weekend, signed off with a 66 at Golf Club Milano to finish on 15-under-par.
Russell Knox (26th) and Richie Ramsay (58th) are the only Scots currently on course to qualify for the season-ending DP World Tour Championship in Dubai with a handful of regular events left on the 2016 calendar.
In addition to that pair and Jamieson, 92nd-ranked David Drysdale is the only other Scot inside the all-important top 110 on the money-list, though Marc Warren (121st) and Craig Lee (126th) just need one good week to secure their cards.
Former SSE Scottish Hydro winner Andrew “Beef” Johnston has secured his PGA Tour card for next season after finishing fourth in the Albertsons Boise Open presented by Kraft Nabisco.
The event was the second of four Web.com Tour Finals tournaments in which PGA Tour cards are handed out to the top-25 finishers on the money list, where the Englishman is sitting sixth after two events with earnings of $54,910.
“I think there will be a Coke or a Fanta or something like that,” replied Johnston to being asked how he planned to celebrate his card success, before adding with a loud laugh: “Nah, there’s going to be a few beers, man!”
He won the SSE Scottish Hydro Challenge at Macdonald Spey Valley in Aviemore in 2014, succeeding Brooks Koepka, who has made the US Ryder Cup team this year, as champion.
Chris MacLean led Balmore to victory in the TSG Scottish Club Championship at Stranraer.
With an aggregate of 282, the Dumbartonshire representatives won by two shots from Cawder with Airdie 10 strokes further back in third.
MacLean claimed the individual honours by three shots after rounds of 70 and 67 for a three-under-par total.
James Wilson and Neil McConachie were the other title-winning Balmore team members.
Dumfriesshire are the Scottish Women’s County champions for the first time after beating Aberdeenshire 5–4 in a thrilling title decider at Aboyne.
After taking the morning foursomes 2-1, Dumfriesshire claimed the crown when Jordana Graham bear Sammy Leslie by one hole in the key singles match.
The win made it six wins out of six for Graham over the three days, a feat also achieved by her foursomes partner, Gemma Batty.
Duddingston’s Ross Munro takes a four-shot lead into the final round of the Sandy Pipey Young Masters at Royal Dornoch.
It followed the ever-improving Edinburgh player opening with an impressive five-under-par 65 at the Sutherland venue.
Eastwood’s Steven Maxwell is his closest challenger while title favourite Paul O’Hara (North Lanarkshire Leisure) has six shots to make up.