Two eagles and six birdies gave the 46 year old Ryder Cup star a ten under par 61 in the Omega European Masters at Crans-sur-Sierre and he goes into the weekend with a three stroke lead.
Jiménez, making his 22nd successive visit to the Alpine resort, had a chance of The European Tour's first-ever 59 when he reached the 16th tee needing two more birdies.
But the Spaniard, who has had ten of his 17 victories on the circuit since turning 40, had to be content with parring all three remaining holes for a 14 under halfway total of 128.
More good news for Ryder Cup Captain Colin Montgomerie was that Italian Edoardo Molinari, the only other member of his side playing in the event, lies joint second with 17 year old compatriot Matteo Manassero.
Molinari, handed a wild card after his win in the Johnnie Walker Championship at Gleneagles last Sunday, added a 65 to his opening 66.
First round leader Manassero, trying to become The European Tour's youngest-ever winner in only his sixth event as a professional, chipped in for eagle at the long 15th in his 67.
But the day belonged to a player who made his European Tour debut ten years before Manassero was even born.
"It was a beautiful day in the mountains," said Jiménez, playing his 535th European Tour event.
"I was thinking 59 a little bit and I tried, but it was still a great round. All the clubs were working properly and that's what you need."
Playing for the fifth week in a row - he added last week's event to his schedule for fear of losing out in The Ryder Cup race and finished third - Jiménez followed three early birdies with an eagle at the 629 yard ninth.
He was on in two with a three wood there, while at the 595 yard 14th he nailed a five wood to within three feet of the flag for his second eagle.
Molinari, also a two-time winner this season, had set the target during the morning with his second bogey-free round.
"I hit the ball great and it was a very controlled and solid round," said the 29 year old, who after this will take three weeks off to rest and then prepare for his debut against the Americans - alongside his brother Francesco, of course - at The Celtic Manor Resort on October 1-3.
A win for wither Jiménez or Molinari would make them the first European since Johan Edfors in 2006 to land three European Tour titles in one season.
Manassero, last year's British Amateur Champion, turned professional only in May at the BMW Italian Open and probably needs a top-five finish to avoid Qualifying School at the end of the season.
This is the sixth of seven invitations he is allowed. The other comes at the Dunhill Links Championship in Scotland next month.
His opening 64 made him the youngest player ever to lead a European Tour event outright after the completion of a round and he resumed with three more birdies in the first four holes.
While he could not keep pace with Jiménez after that he was still delighted with his performance knowing what is at stake.
“It wasn’t an easy day and I made four under par which is still a good score,” he said. “I’m going to be close to the leader tomorrow and hopefully in the weekend.”