Leicester boss Richard Cockerill admitted the Tigers had 40 minutes to save their season as they posted a thrilling 35-30 comeback victory over Gloucester at Welford Road.
England centre Manu Tuilagi scored two tries and created another as Leicester strengthened their Aviva Premiership play-off hopes, but only after the the Tigers had trailed by 17 points approaching half-time.
Tuilagi's double, plus touchdowns by his midfield partner Peter Betham, full-back Telusa Veainu and wing Vereniki Goneva's 74th-minute clincher ensured that Leicester triumphed in bonus point fashion, with fly-half Owen Williams kicking 10 points.
"I am delighted with the result, delighted that we got ourselves out of the hole that we put ourselves in," Cockerill said.
"But I am really unhappy with that second 20 minutes, which wasn't good enough and not acceptable from us. If you play like that, you get what you get at half-time, which was a 14-point deficit.
"We had dominance in the game, but I think that permeated into us being a bit lax and a bit sloppy. There was poor defence and poor decision-making in that second 20 minutes, and they have got good enough players to punish you, which they did.
"I was pretty unhappy at half-time, if I am honest. We were good enough to win the game, but some of the things we did in that second 20 minutes were not acceptable.
"We had 40 minutes to save our season, because if we had lost today, we were done. We knew if we got it right, we are a good enough side to claw it back, so credit to the players for doing that.
"It was a great win, and we will take a lot of spirit from the win.
"Five points keeps us well alive in the competition, but if we are happy with part of that performance, we are kidding ourselves, and we need to make sure we understand that. There were so many positives to take out of the game - we did some good things.
"There were some harsh words said at half-time because I thought they were necessary. If we had lost, the season was done. I had no doubt we could win if we got certain things right."
It was perhaps rough justice on Gloucester, who scored three tries during nine blistering first-half minutes from wing Steve McColl, centre Henry Trinder and prop Paddy McAllister, while skipper Greig Laidlaw kicked three penalties and three conversions for a 15-point haul.
But Leicester possessed just enough composure and experience to close out a pulsating contest as they kept in touch with Premiership top three Saracens, Exeter and Wasps.
Gloucester rugby director David Humphreys said: "I am hugely proud of the players, but also hugely disappointed for them.
"We played with some real ambition, scored some great tries and defended well, but ultimately we will look back and three of Leicester's tries came from our set-piece. If you want to come to Welford Road and win, that is one of the parts of your game that has got to be rock solid.
"Our performance was a lot better today. We showed real ambition to play. We came to a tough place against a top-four team and produced a performance that the players can be proud of.
"I thought there were a lot of very good individual performances, but it was more the ambition throughout the team to try to play. We talked all this week about coming to Welford Road, trying to play and coming away with a big performance.
"When we sit back and reflect on the game, we will be unbelievably disappointed to have gone in at half-time 27-13 up and not to have closed out the game."