Wayne Pivac accepts that all Wales can do is "sit back and watch" as their Guinness Six Nations title fate is decided.
Wales' Grand Slam hopes were destroyed by France in the final play of an epic Paris encounter, losing 32-30 after being reduced to 13 players when Taulupe Faletau and Liam Williams were sin-binned 60 seconds apart.
And a sixth Six Nations crown for Wales now hinges on what happens in next Friday's game between France and Scotland.
The Stade de France clash, delayed because of a coronavirus outbreak in Les Bleus' camp last month, will see the hosts start as overwhelming favourites.
They need a bonus-point victory and winning margin of 21 points or more to pip Wales to the post.
If France win in bonus-point fashion and take the match by exactly 20 points, it will come down to tournament try-count between Les Bleus and Wales. Anything less – or Scotland win or draw – and Pivac's men prevail.
Wales have currently scored five tries more than France, and should overall points totals, the countries' points differences and try-counts finish level, then this season's Six Nations title will be shared.
Pivac's team have scored more tries and points than in any other Six Nations campaign, yet they must now hope that France come up short.
And the odds are not favourable for Wales, given that France have beaten Scotland in all ten previous Six Nations meetings at the Stade de France.
"It is just desperately frustrating," Wales head coach Pivac said.
"The players got so close and yet so far. It is a tough time for them.
"We have to be proud of the performance, proud of the effort they have put in throughout the championship, and now we go away and wait to see the outcome of next Friday's game.
"To go from potentially a Grand Slam performance to sitting back and waiting is frustrating, but there is nothing we can do now except sit back and watch that game."
France, having seen lock Paul Willemse sent off 11 minutes from time for making contact with the eye area of Wales prop Wyn Jones, prevailed through full-back Brice Dulin's stoppage-time try.
It was Wales' first defeat in a Six Nations Grand Slam game, having won their previous four in 2005, 2008, 2012 and 2019.
Wales had matched France try for try until that point, with fly-half Dan Biggar, flanker Josh Navidi and wing Josh Adams touching down during an incident-packed blockbuster.
Biggar also kicked 15 points, yet Wales were ultimately eclipsed as the clock ticked past 11pm in Paris when Dulin scored after clinically capitalising on France's one-man advantage.
Navidi said: "It just didn't go our way, but it has been a good campaign for us from the autumn (Autumn Nations Cup) to the Six Nations, and how many points we scored in this campaign has been good.
"It was a shame we couldn't finish it with a win and see it off, but fingers crossed that next Friday goes our way.
"The autumn wasn't that great, but we came into this Six Nations knowing what we wanted to achieve. We said from the start that we have the squad to do it, and we built on it every week.
"In the last 20 minutes we were under the pump, and it is only going to go one way if we are in our own half, defending and giving away penalties."
