The Scot downed David Ferrer 5-7, 6-2, 7-5 to claim the title on his first appearance in the Austrain capital to move ahead of the Spaniard into the final qualifiyng spot for the season-ending finals in London.
With five of the eight places already secured and US Open finalist Kei Nishikori almost guaranteed his Tour Finals debut, there is a five-way battle between Murray, Ferrer, Tomas Berdych, Milos Raonic and Grigor Dimitrov for the remaining slots.
"Every event is so important now with the race for London going strong," said Murray, who will be playing in his fourth event in as many weeks.
Murray's victory in Vienna moved the 2013 Wimbledon champion 110 points clear of Ferrer, who also has 300 points to defend in Valencia having been beaten by Mikhail Youznhy in last year's final.
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The two are on course for another meeting in the semi-finals with three-time champion Ferrer the top seed and Murray seeded third.
And Ferrer is determined to take his battle down to next week's final qualifying tournament at the Paris Masters.
"Andy played a great match and deserved to win the title," said the 32-year-old.
"I had my chances but it was so tough today. I'm going to keep fighting for London."
Berdych's 10th career title in the Swedish capital kept his Tour Finals bid on track and the second seed appears to have an easier draw in Valencia.
"I think it is going to be a really interesting end to the year, I just need to be prepared and go for it again.
The Czech starts off against Spaniard Pablo Andujar and could face American John Isner in the last eight.
Murray is up against Austrian Jurgen Melzer, whilst Ferrer faces Italian Andreas Seppi in the first round.