Jimenez began the final round leading by two and he looked to have the event in safe keeping when he set up a short birdie putt at the 14th which would have moved him four clear of the field.
He would miss that putt and with Bernhard Langer finishing strongly and the vagaries of St Andrews finishing stretch ahead of him nothing was guaranteed.
The crucial hole would the notorious Road Hole 17th and although long with his approach he was able to two-putt from near the 18th tee for par, the second of those from 12 feet or so.
That kept him one ahead playing the last and, in the group ahead, the defending champion Langer was unable to secure the one final birdie he needed to force the issue and Jimenez would par to win by one over Langer.
Americans Scott McCarron and Kirk Triplett and Canadian Stephen Ames finished in a share of 3rd one shot behind Langer.
Jimenez was emotional and excited in winning at such an iconic venue.
“It’s amazing to win here at St Andrews; it’s a place where so many people want to win and where Seve played so well in The Open. Now my name is part of history.
“This is one of my biggest victories. It’s amazing to win here. This is my second Major of the year, and it’s amazing to be the winner of The Senior Open here at St Andrews, the Home of Golf.
“There are no words to describe the feeling of holding the trophy on the 18th green. To have that trophy in my hand in front of the crowd and my friends, and my family is amazing."
David McKenzie finished as the leading Australian in 14th place, Peter Lonard was 24th, Peter Fowler 28th and qualifier Paul Archbold a very respectable 32nd.
KIERAN PRATT TOURNAMENT PUTTING WARM UP
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