Slovenian Matej Mohoric clung onto the Tour of Poland lead by a slim margin after Thursday's penultimate stage won by Italy's Mattia Cattaneo.
The seven-day race will go down to the wire with Mohoric on the same time as Portugal's Joao Almeida after the 16km sixth stage time-trial at Katowice.
Almeida finished second behind Cattaneo on the day with Mohoric clocking the 11th fastest time to hold a slim tenth of a second advantage on Almeida.
The race will be decided in Friday's 166km final stage in Krakow which includes two intermediate sprints.
Poland's Michal Kwiatkowski, third overall at 14sec, and Belgian Ilan Van Wilder, fourth at 19sec, can still hold out hope for final victory. But for Cattaneo in fifth at 38sec it will be a long shot.
The Italian from the Soudal-Quick Step team consoled himself after Thursday's win, just the fourth of his career, aged 32 years.
"The time trial is my speciality and it bodes well before the worlds," said the Italian, second in the national championships in the discipline behind Filippo Ganna.
STAGE
1. Mattia Cattaneo (ITA/Soudal-Quick Step) 19min 10sec
2. Joao Almeida (POR) at 13sec
3. Geraint Thomas (GBR) 14
4. Finn Fisher-Black (NZL) 16
5. Tim Wellens (BEL) 17
6. Ilan Van Wilder (BEL) 18
7. Kevin Vauquelin (FRA) 18
8. Michal Kwiatkowski (POL) 21
9. Tobias Foss (NOR) 21
10. Brandon McNulthy (USA) 24, 11. Matej Mohoric (SLV) 25
OVERALL STANDINGS
1. Matej Mohoric (SLV/Barhain-Victorius) 22hr 49min 07sec
2. Joao Almeida (POR) s.t.
3. Michal Kwiatkowski (POL) 14
4. Ilan Van Wilder (BEL) 19
5. Mattia Cattaneo (ITA) 38
6. Brandon McNulthy (USA) 39
7. Edwar Dunubar (IRL) 52
8. Rafal Majka (POL) 55
9. Samuele Battistella (ITA) 57
10. Oscar Onley (GBR) 1:04.