Andy Murray and brother Jamie put Britain within touching distance of a first Davis Cup tennis triumph for 79 years with victory over Belgium duo David Goffin and Steve Darcis in the doubles.
A match played out in an electrifying atmosphere ebbed and flowed before the Murrays carved out a 6-4 4-6 6-3 6-2 victory to put Britain 2-1 ahead.
The final will be decided tomorrow morning with the two reverse singles.
World number two Andy Murray, who was inspirational again as he has been throughout Britain's run to a first final since 1978, can deliver the winning point in tomorrow's first reverse singles against Belgium's top player Goffin.
Older brother Jamie wavered at times, but he held his serve to finish the match off when Darcis screwed a forehand wide, signalling wild celebrations from the British fans wedged into the claustrophobic 13,000-seat arena inside the Flanders Expo.
"There was so much noise, it was mental. We were shouting to each other at times but it's brilliant, and it's what you expect with so many passionate fans here for the final," Jamie said.
Belgium made a late change to their doubles line-up with world number 16 Goffin replacing Kimmer Coppejans.
He played superbly from the start of the match but his partner lashed an easy overhead long at 4-5 to give Britain set point which Andy Murray converted with a volley.
Jamie, the one pure doubles specialist on the court with a ranking of seven and two grand slam finals on his CV, was the weaker link in the second set and dropped serve in the third game as the Belgians roared back into contention.
Britain had the chance to break back at 2-3 but, for once, Andy Murray's return let him down.
Goffin's sharp volley winner with Darcis serving at 5-4 levelled the match, the accompanying roars shaking the steel girders looming low over the illuminated claycourt.
Things swayed towards the hosts when Jamie Murray dropped serve early in the third set but the British siblings broke twice in a row to lead 4-2 before Jamie again lost his serve.
Darcis's delivery was proving equally vulnerable though and Britain pounced to move 5-3 ahead and Andy Murray, Britain's Mr, Reliable, held firm.
The shaven-headed Darcis was broken again in the third game of the fourth set to put Belgium in deep trouble.
Seven break points went begging for the Belgian duo when Jamie Murray served at 2-1 and with them went the hosts' chance of dragging the match into a deciding set.
Andy Murray has now been involved in 10 of Britain's 11 winning points this year and needs one final push on Sunday to end his country's long wait for a 10th title.