He has predicted GDP growth of 3.3% for the islands, a rise from this year's 3.1%. The second and third most prosperous areas were Aberdeen and Aberdeenshire.
Mackay ascribed the islands' performance to the current oil and gas boom, and the building of Total's £800 million gas terminal at Sullom Voe.
Shetland council's head of economic development, Douglas Irvine, said the Total project was employing 2000 people - the islands have a population of 23,000 - and was worth £20m a year during construction. It should be finished in 2014-15.
Irvine said the problems the islands faced were providing accommodation for building workers, and stresses on the housing market caused by high housing allowances paid by Total. "The development hasn't yet put pressure on schools and hospitals but road services have been impacted. The roads here are very busy," he said.
Shetland's low unemployment rate - currently around 0.8% - means the council, which employs 2000, has shed 500 staff since 2010 and seen them absorbed into the labour market. After oil and gas and public services, Shetland's biggest industry is fisheries which has not suffered badly in the recession.
In his Scottish Economy Monthly report for January, Mackay said the areas with the lowest growth forecasts for 2014 are South Ayrshire and the Scottish Borders +1.9%, Falkirk at +1.8%, and West Dunbartonshire at +1.7%, all better than at any time since the recession began in 2008.
"We expect Glasgow to have a higher-than-average growth rate of +2.5% in 2014, partly because of the Commonwealth Games. In contrast, our Edinburgh forecast of +2.1% is a little below the Scottish average of +2.3%".