Graham’s four tries upon his international comeback versus Fiji after almost 13 months out at the start of November took him level on 28 with his fellow winger but that parity only lasted ten minutes as the South African scored another after his team-mate was forced off by a head injury.
The ex-Green will retain joint possession of top spot at least until Sunday this time round, though, as 43-times-capped van der Merwe, 29, was rested at the weekend, though he might well return to the fold alongside Graham for the Scots’ final test of the year hosting Australia.
Kick-off at Murrayfield this coming Sunday is at 1.40pm and head coach Gregor Townsend will name his team to take on the Australians on Friday.
They go into that game on the back of three wins in their last four games against the Wallabies, the odd one out being a 16-15 defeat at Murrayfield last October.
Right-winger Graham, 27, was one of three fellow Borderers in Townsend’s match-day squad of 23 versus the Portuguese, with hooker Patrick Harrison being given his first start and loosehead prop Rory Sutherland being brought on as a 50th-minute replacement for former Melrose man Jamie Bhatti.
Bhatti, 31, was also among the Scots’ try-scorers, touching down for the first time for his country on 43 minutes, ten minutes after Graham got the hosts’ third.
Scotland’s other tries, accompanied by a 27th-minute penalty try, were scored by tighthead prop Will Hurd on three minutes, captain and inside-centre Stafford McDowall on 11, No 8 Josh Bayliss on 37, left-winger Arron Reed on 58 and 61 and replacement scrum-half Jamie Dobie on 72, with fly-half Adam Hastings adding five conversions and full-back Tom Jordan one.
Luka Begic, Samuel Marques and Raffaele Storti scored tries for the visitors, with Marques converting all three.
Graham played for the full 80 minutes for his 41st cap and Harrison, 22, for 64 for his third, with Sutherland, 32, picking up his 36th cap and Bhatti his 35th.
Hawick’s Stuart Hogg and Tony Stanger remain respectively third and joint-fourth with Ian Smith on Scotland’s all-time try-scoring chart, on 27 and 24.
Ex-Gala and Border Reivers player Townsend was delighted to see Graham last the entirety of what was only his second international appearance in 13 months, saying: “The fact he got 80 minutes was a real positive.
“He had to take a few hits as well, more from him tackling than being tackled.
“He’s now equal with Duhan, so that’s a sub-plot story that will continue next week and throughout the season, no doubt.”
The 51-year-old was also pleased to see his side rack up their second victory in three autumn tests, adding: “Portugal brought a lot of physicality and line-speed that we had to adjust to and find solutions and the players did that.
“The first half was probably more clinical at times, once we got through a sticky five to ten minutes. The second half, with the changes we were making and the fact we didn’t have as much possession, maybe it wasn’t as fluent, but that was a good performance and a very good win against a test team.”

1. Scotland v Portugal
Patrick Harrison on the attack for Scotland during their 59-21 win against Portugal at Edinburgh’s Murrayfield Stadium on Saturday (Photo: Bryan Robertson) Photo: Bryan Robertson

2. Scotland v Portugal
Rory Sutherland in action for Scotland during their 59-21 win against Portugal at Edinburgh’s Murrayfield Stadium on Saturday (Photo: Bryan Robertson) Photo: Bryan Robertson

3. Scotland v Portugal
Darcy Graham on the ball for Scotland during their 59-21 win against Portugal at Edinburgh’s Murrayfield Stadium on Saturday (Photo: Bryan Robertson) Photo: Bryan Robertson

4. Scotland v Portugal
Darcy Graham after helping Scotland beat Portugal 59-21 at Edinburgh’s Murrayfield Stadium on Saturday (Photo: Bryan Robertson) Photo: Bryan Robertson