Technical problems dogged the “gaffe-strewn” edition of Reporting Scotland, and most of the items were abandoned.
The descent into chaos began when the studio lost a live feed from golf correspondent Phil Goodlad, who was at the Open Championship at Muirfield.
He was halted mid-sentence, forcing Magnusson to apologise and try to move on to an item about Scots artist Ken Currie.
But a second fault saw her abandon the piece and skip to a report about tennis star Andy Murray, just as Currie’s picture came into view.
Attempting to keep her cool, Magnusson folded her arms and said: “Oh, it’s a wee bit of a dog’s breakfast – I do apologise.”
Waiting a moment to be advised by producers how to proceed, she told viewers: “They’re having a little argument.”
The 57-year-old broadcaster then said, “Apologies … let me tell you about Ken Currie again”, as she rifled through her paperwork to find the arts story.
After fluffing her lines as she invited viewers to rejoin her for the early-evening edition of Reporting Scotland, Magnusson finally lost her composure.
Live on air, she leaned back and spread her arms before letting out an exasperated howl as the programme ended.
Viewers took to Twitter to voice their amusement.
James Christie, from Perth, applauded her handling of the situation. “Sally Magnusson on BBC Scotland just showed why it’s useful to have an experienced anchor when the news disintegrates into technical chaos”, he wrote.
David Ross, from Glasgow, wrote: “I think Sally Magnusson is my new hero.”
Ian Hoey said: “That was indeed superb television. Think she handled it very well and with good humour.”
Another viewer said that the hot temperatures – Glasgow hit 25C yesterday – might have affected Reporting Scotland’s usually reliable broadcast. “Sally Magnusson with a lot on her plate this afternoon. The heat is getting to her,” Ian Mo wrote.
A BBC Scotland spokesman said: “We experienced a number of problems which began with a failed link during a report from the golf at Muirfield. We would like to apologise to viewers for the disruption to the bulletin.”
Magnusson, the daughter of the late broadcaster and writer Magnus Magnusson, had regained her composure by the time she faultlessly fronted the main evening edition of Reporting Scotland.
The technical hitch on the lunchtime programme was the second blow for BBC Scotland this week, after a review carried out by the corporation found fewer than half its audience thought it was good at representing their life in its coverage of news and current affairs.
The BBC Audience Council –which advises the BBC Trust on the views, needs and interests of audiences – said the corporation should be “more searching” in comparing differences in policy in the disparate parts of the UK in the wake of devolution.
Only 48 per cent of people in Scotland believed the corporation did well at this – the lowest proportion of any of the countries in the UK.