Stepanek unleashed a forehand shot during his first round French Open clash against Murray.
Instead, it will be the first time since 1975 that there will be three British men in the French second round, with Aljaz Bedene having won earlier 4-6 6-3 6-4 6-4 versus Austrian Gerald Melzer.
The relieved World No 2 said afterwards: ‘He played incredibly well. He is always extremely difficult to play. He hardly missed a volley and was serving well. He used a lot of dropshots and was serving very well. I wasn’t able to dictate the points and didn’t get much rhythm and that’s credit to him.
‘I knew yesterday when we stopped but I knew also that anything could happen in a fifth set. I only just made it at the end when he made a couple of mistakes.’
Had this match been played to its conclusion in one go then the Scot was a near certainty to win, but circumstances dictated that the veteran benefitted from an overnight rest.
On a chill and overcast lunchtime, resuming at 4-2 in the fourth, Murray came out and was given quick notice that Stepanek had no stiffness after the previous evening, his movement again remarkably sprightly.
Murray (right) congratulated the 37-year-old Stepanek on his valiant display after the match was over
Stepanek produced a dynamic display against Murray, which engulfed the crows at Roland Garros
Murray stretches to reach the ball in his gripping first round encounter against Stepanek in France
Czech Stepanek continued to dig deep against Murray and provided some impressive resistance
He forced two break points in the opening game, but then had to save a set point himself after missing them. A firm hold from Murray meant that he would be serving second in the decider.
The Czech was missing a few backhands but his serve and returns were in prime working order. Murray forced a break point in the first game, which was saved by Stepanek rushing the net, something he did to excellent effect.
Murray forced another break point at 2-2, which was headed off by a serve and volley manoeuvre. The Czech was winding the crowd up, and doubtless his opponent, by waving his arms in the air and beating his chest, as is his wont.
He looked the likely winner when his precision dropshots and volleys carried him to deuce at 4-5, backed up by exceptionally accurate serving.
But Murray eventually broke his serve in the 11th game of the fifth set to put victory in sight
The fifth set lasted 71 minutes before Murray managed to break Stepanek and seal victory
Stepanek dumped a volley into the net on match point to hand Murray victory after five sets
Murray was clearly relieved to have seen off the Czech in the opening round of the second Major this year
But after Murray held with an ace for 5-5 Stepanek without warning played a dreadful game, throwing in three groundstroke errors and a double fault.
Murray then served a double fault on his first match point, but just about managed to close it out when the Czech netted a forehand volley on the second.