London Welsh boss Lyn Jones vowed that his team will "keep plugging away" in their fight to avoid relegation from the Aviva Premiership.
The Exiles' heartbreaking 15-14 defeat at Gloucester - following Freddie Burns' 75th-minute penalty - left them five points adrift at the Premiership basement with four games left.
"When I joined London Welsh I said there wasn't an experience in rugby that I hadn't come across, but I was wrong. What is going on is another test that is energy-sapping," Jones said. "We just (need) to try to keep our focus on what we can influence, which is results and the scoreboard. We need to keep believing."
Welsh's position could change early next week after they appealed a five-point deduction for fielding an ineligible player - scrum-half Tyson Keats - in the Premiership this season. The result of their appeal hearing is expected to be made public within 72 hours.
And they need it to work in their favour, given that their remaining Premiership fixtures are away against Bath and London Irish, plus home appointments with Northampton and Worcester.
Jones added: "When you are a professional sportsman, 80% of the time is dealing with rejection and disappointment, and you have to have a mental toughness to deal with that. There is nothing we can do in terms of the appeal, but when we are on the field we can do something about it, which is what I keep telling the players.
"We need to turn up next Saturday at Bath and do the best we can, and then likewise against Northampton, London Irish and Worcester. Can we win the four games? Potentially, we can."
Wing Phil MacKenzie's 52nd-minute try and three penalties by fly-half Gordon Ross put Welsh on the verge of only their fifth league win this season, but Burns' five successful penalties - he also missed four shots at goal - kept Gloucester on course for the title play-offs instead.
Gloucester rugby director Nigel Davies said: "I am relieved at getting the four points. London Welsh made it very difficult for us, which we knew they would. They had a real cause today, and they represented that cause very well.
"We didn't play well. We have got to look long and hard at ourselves. We don't want to perform like that, we want to play a bit more rugby, but unfortunately we couldn't do that."