Home favourite Bernd Ritthammer carded five birdies to join overnight leader Robert MacIntyre at the top of the leaderboard, setting up a tense finale heading into the final round of the European Open in Germany.
Scottish rookie MacIntyre started at Hamburg's Green Eagle Golf Course on Saturday with a four-shot advantage but saw his lead evaporate at the turn as he dropped two strokes while playing partner Ritthammer sank two birdies.
Successive birdies on the back nine saw Ritthammer move two shots ahead with five holes remaining but a late wobble allowed MacIntyre to draw level at nine-under-par overall.
Ritthammer, ranked 924th in the world and fighting for his European Tour card for next season, recovered with a final hole birdie to sign for a two-under-par 70, while MacIntyre finished with 74.
"There are a lot of thoughts going through my head right now but it was definitely an experience for me," Ritthammer said.
"We have fantastic crowds out there. I got a lot of support today, which is unbelievable.
"I'm not used to leading an event on the European Tour. It was tough on the back nine but those last two or three holes were back to good golf and hopefully I can continue that tomorrow."
England's Paul Casey recorded birdies at the second and third holes to set the tone for the day and remained in contention with a 69, one shot behind the co-leaders.
Yet Casey, a 13-time European Tour winner, would have been disappointed that he could not convert birdie opportunities on the final three holes.
Spain's Pablo Larrazabal mixed seven birdies with three bogeys to finish on seven-under alongside Austria's Matthias Schwab.
World number nine Xander Schauffele had a day to forget as he carded seven bogeys in a round of 76, 11 shots off the lead.