Gloucester face a massive challenge to regroup and head into three games that will shape the end of their season after a bitterly disappointing reverse at Franklin's Gardens.
Two late tries starved the Cherry and Whites of any match points in their fight to be among the coveted top four come the end of this Guinness Premiership campaign.
With the EDF Energy Cup final against Cardiff up next, Dean Ryan's men have everything to play for, but the performance will have to be a step up from the one which shipped four tries, including two in the final three minutes, against a rampaging Northampton Saints.
The hosts went ahead on four minutes through a Stephen Myler penalty after Gloucester were adjudged to have killed the ball on their own 10 metre line, it not taking them long to do what the Ospreys couldn't for 80 minutes last week.
Ryan Lamb missed a chance to reply immediately, his effort hitting the post from a similar position in the other half.
The first Saints try came with almost their first attack. Mark Foster was turned over and the ball moved quickly left for skipper Bruce Reihana to cut in and break. Three phases later the ball was back on the right flank and winger Paul Diggin ran in the simple score, which Myler converted.
The Cherry and Whites needed a response, and they got one almost immediately. They had just bombed a massive opportunity to score when Akapusi Qera turned the ball over and Gloucester had a huge overlap. But Lamb, Matthew Watkins and Foster combined to miss the chance and turn the ball over for a home scrum.
But from a breakdown seconds later, Lee Dickson's attempted drop kick was charged down by prop Nick Wood, who collected and scored simply, Lamb hitting the other post with the conversion.
Just when a period of consolidation was what head coach Ryan's men needed, up popped Reihana again after a poor Lamb kick through. He stepped Olly Morgan and beat Rory Lawson before finding Dylan Hartley via Neil Best for a simple finish, Myler slotting the conversion from touch.
The high scoring continued and it was Gloucester who registered next. Reihana turned villain by passing into touch and from the line-out Morgan made good ground out wide. Will James took it up before Akapusi Qera got his hands on the ball and carried a vital 10 metres with three players hanging off him. James was on hand from the breakdown to reach out and put the ball down with Lamb finally finding range with the conversion, 17-12.
Myler extended the Saints lead with a penalty before the Gloucester backs kicked into gear. After a Dickson kick over, Lamb collected and found Morgan, who drew three defenders before finding Foster. The winger came and pace and showed good strength to beat Foden and score, Lamb slotting the touchline conversion to bring Gloucester within a point.
Another Myler penalty extended that lead to four before the break, and it was an altogether tighter affair at the start of the second 40.
Lamb missed an early penalty and was then part of a triple substitution, Carlos Spencer, Olly Barkley and Carlos Nieto all coming on.
Barkley was soon called into action to slot a long-range penalty but Myler replied with one of his own minutes later after Andy Hazell was sin-binned for a clash with Dylan Hartley.
Gloucester managed not to concede during the 10 minutes they were down to 14-men, and when Hazell return they struggled to get out of their own half, spending much of the time defending.
Their one chance game inside the last 10 minutes, but ended when Alex Brown was adjudged to have held on for too long.
The Saints surged back up the other end, and after a series of phases Reinhana found his way over under the posts to land a killer blow. As both sides chased a bonus point, Reinhana broke again and found Diggin to really rub the away side's noses in it.
Written by, Gareth Butler