His superb strike was good enough to earn Saracens 12-11 victory over Racing Metro 92, a third semi-final appearance in as many seasons and a last four showdown with ASM Clermont Auvergne in St Etienne.
 
They will collide at Stade Geoffroy-Guichard for a place in the final but Racing will be kicking themselves for not making the game safe after Heineken man-of-the-match Maxine Machenaud had edged them back in front with just minutes left on the clock.
 
They failed to keep Saracens out of goal kicking range and Bosch punished them to ensure there will be English interest in the last four.
 
Racing, with five wins and a draw from their Pool 5 contests, were appearing in their first tournament knock-out match and will see this as a chance lost to really make their mark in Europe.
 
For Saracens it was a tribute to their never-say-die attitude and their pack demonstrated they were well and truly up for the challenge by all but destroying the Racing scrum.
 
And outside half Charlie Hodgson complimented their efforts by nailing the fifth minute penalty goal.
 
That briefly silenced the vociferous home crowd but that was soon replaced by a barrage of whistles as Welsh referee Nigel Owens penalised Racing three times in as many minutes.
 
Welsh centre star Jamie Roberts produced one of his trademark Route One surges but unforced errors meant Racing were unable to build any sustained momentum.
 
One of those errors came as they lost possession at the critical moment after a tremendous forward drive had Saracens in rapid reverse gear, TMO Derek Bevan making the key decision to more howls of disapproval.
 
But there was woe for Saracens when Jim Hamilton was yellow carded by referee Owens for his infringement at a ruck on the visitors’ line and Racing promptly took advantage of being a man to the good from the line-out.
 
The forwards drove it on and livewire scrum half Maxime Machenaud took control to drive over for the opening try. Jonny Sexton’s conversion attempt bounced back off the upright but Racing were ahead for the first time after a tight opening half hour.
 
Superb play by Brice Dulin – backed up by Roberts – had Sarries on the back foot but a second Hodgson penalty goal success on the stroke of the break edged them back in front by a single point with the contest finely balanced.
 
Racing had had the better of both possession and territory but Saracens’ refusal to give an inch had served them superbly.
 
With Hodgson requiring some lengthy treatment Alex Goode took over kicking duties and his penalty success early in the second half pushed them four points clear.
 
Sexton made a hash of the restart, kicking it far to long, and restlessness in the stands could only work to Saracens’ advantage.
 
Dulin was again the inspiration for Racing, although his scintillating break came to nothing when Juan Imhoff lost the ball with the line beckoning.
Racing stole Saracens’ scrum ball but yet another home team infringement enabled Saracens to lift the siege.
 
Imhoff departed after Sexton’s knee came into contact with his team-mates head – both side sending on rafts of replacements going into the final quarter of a punishing contest.
 
Machenaud proved equally as effective with the boot as he had with the hand, firing over a penalty that cut the deficit to just a point, as Saracens found themselves under hammer.
 
Goode took the pressure off with a fine side-stepping run but Racing took the lead for the second time with Machenaud landing his second penalty to belatedly get the crowd involved again.
 
But the drama went right into overtime, Racing penalised and Bosch keeping his nerve to fire over a long range penalty that brought delight to the small band of travelling support and despair to home fans.