The Swede arrived in Prague off the back of four missed cuts but a stunning run of scoring around the turn and a birdie on the last propelled him to ten under as he equalled the course record in the Czech capital.
Australian Maverick Antcliff, South African duo Dean Burmester and Jacques Kruyswijk, Dane Søren Kjeldsen, Finn Tapio Pulkkanen and American Johannes Veerman were then at seven under on a congested leaderboard at Albatross Golf Resort.
Soderberg had graduated from the Qualifying School and the European Challenge Tour before a stunning victory in a five man play-off that included four time Major Champion Rory McIlroy brought his maiden European Tour victory in Switzerland in 2019.
He was 194th on the Race to Dubai Rankings in Partnership with Rolex coming into this week but looks to have found his groove at the perfect time and could head to the mountains to defend his title next week with a second win under his belt.
"I did play really well," he said. "I didn’t really get into trouble, except on 17 and I made a good up-and-down. It was a lot of fairways, a lot of greens, a few nice putts and a very solid day.
"It’s been a tough year so far, I decided to take a longer break this summer. It’s my first event in five or six weeks. I took a pass earlier with my swing coach, who I’ve been with for 13 years. I started to work with him again this summer and it’s feeling pretty good again.
"It’s going to be a bit rusty but I’ll try and play one hole at a time. I’m sure there’s going to be some pressure, hopefully it’s not too bad and I can manage it and keep playing well."
Overnight leader Stenson made the perfect start as he got up and down to birdie the tenth but then made eight pars in a row as those around him jostled for position.
Crocker holed from nearly 40 feet on the 14th and then put his tee shot to ten feet on the par three 16th to join Stenson at six under but the 45-year-old hit the green in two at the first to edge into the lead.
It’s going to be a bit rusty but I’ll try and play one hole at a time
A two putt birdie from Crocker on the same hole had him at seven under and he put an approach to three feet at the fourth before Stenson put his tee shot at the par three seventh even closer. Crocker then almost drove the green at the par four sixth and he was the solo leader.
Meronk got up and down on the first, holed a 23 footer on the third, made an excellent recovery from a poor tee shot to birdie the fifth and then got up and down from the sand to get within one of the lead.
Torrential rain led to a 30 minute delay while the 28-year-old was playing the tenth and upon the resumption he recorded a double bogey, earning a one shot penalty after his caddie stepped on his ball.
Soderberg had birdied the first and second but gave a shot back with a three putt on the next before holing from distance on the fifth and eighth.
He birdied the tenth and 11th to creep further up the leaderboard and then holed a 20 footer for eagle on the 12th to take a share of the lead.
Meronk bounced back from his double at the tenth with a birdie on the 11th and when he chipped in at the 13th and spun an approach inside two feet at the 15th, there was a three way tie.
Soderberg then put his second from 154 yards to a foot at the last to hit the front on his own.
Pulkkanen had held the lead at nine under but double bogeyed the 16th in a 69, a score matched by Burmester.
Veerman was bogey free in his 66, Kruyswijk dropped a single shot in a 68 and Antcliff recorded four birdies and two bogeys in a 70.
Kjeldsen put on a masterclass with the putter, holing long putts on the seventh, ninth and 14th in a bogey free 67 to sit a shot clear of 2016 champion Paul Peterson.