Andy Murray's hopes of reaching a maiden French Open final hang in the balance after rain saw a suspension to the semi-final with world number one Novak Djokovic at Roland Garros.
Djokovic led by two sets to one when the match was halted midway through the fourth set due to an incoming storm in Paris with the match set to resume at none on 6 June.
Murray had looked to be crashing out of the semi-final stage for a third time as Djokovic stormed into a two-set lead as the Serbian to another step towards clinching a career grand slam.
The eight-time major champion missed break points in the sixth game of the third set and that saw a swing in momentum as Murray won the final three games in a row to force a fourth set.
The British number one grabbed an early break only for Djokovic to break back straight away, before a deluge of rain fell at 3-3 to bring an untimely end to the match which will go into a second day.
Earlier, Wawrinka thrust himself in just his second grand slam final after ending Tsonga's hope of becoming the first French male to win at Roland Garros since 1980.
Tsonga carried the hopes of a nation into just his second last four outing at his home grand slam but suffered from nerves throughout as Wawrinka's powerful groundstrokes saw him soar into the final with a 6-3 6-7 6-7 6-4 victory.
"When I play my best I know I can beat all the players," he admitted. "I've been playing really well since the beginning of the tournament. I'm surprised & really happy with how I've been playing."