The Englishman carded a bogey free 64 to sit two shots behind leader Garrick Higgo after 54 holes at Golf Costa Adeje but this will not be his first time in the final group on a Sunday despite him playing in just his ninth European Tour event.
He was in the same position last summer at Golf Club Adamstal and finished second to Joël Stalter as he continued his rise in the golfing world.
The 26-year-old enjoyed an impressive collegiate career in the United States before turning professional in 2017 and finishing second on the EuroPro Tour Rankings in 2019.
His maiden European Challenge Tour season saw him finish in the top five on the Rankings to earn his place on the European Tour, and he believes his exploits at the co-sanctioned event in Austria will stand him in good stead - both on Sunday and beyond.
“I finished second at Euram Bank last year,” he said. “It was a co-sanctioned event, so a win would have got me my card.
“I didn’t and I had a little moment there on the 15th where I went to tap it in for birdie to tie the lead with three to play and missed it. Careless mistake, bit of a rookie error.
“Potentially that could have been the best thing that happened to me not winning there. Would rather do that in that event rather than the Open or the Masters one day.
“Learn from it, try to keep getting better and that’s what I’m doing. Happy with the progress.”
Mansell turned in 31 with birdies on the first, fourth, fifth and ninth and led by two when he added three more on the 13th, 14th and 17th.
But he could not keep Higgo at bay as the 21-year-old - who had earlier carded two eagles, two bogeys and a birdie - finished with four gains to get to 20 under.
"I've seen guys going low on this course for two weeks now," said Mansell. "I feel like I've played a few rounds where I could have gone really low and didn't.
"I wanted to cut out mistakes and thankfully my short game was good today. Holed a few putts, which for the last few weeks has been missing. I've already said if I can putt well I'll be there or there abouts.
"The biggest mindset aim was staying gritty and not letting bad stuff phase me. I had a couple of holes where I had a wobble in the middle to back end of the front nine and my short game got me out of trouble. That's what you've got to do at this level."