Saints were beaten 27-14 at Mattioli Woods Welford Road, seeing their dreams of a Twickenham showpiece slip away.
Skosan had a difficult day as he missed some big chances that he would usually take, with the South African winger knocking on three times during the first period.
He was also denied by a huge try-saving tackle from Guy Porter, who could have seen red before the break for a dangerous high tackle on Rory Hutchinson, in the second period.
And eventually Saints lost their way as referee Matthew Carley showed a yellow card to Oisin Heffernan for a seatbelt tackle that many felt only merited a penalty.
Tigers took control and George Ford stuck the boot in to send table-topping Tigers to Twickenham, where they will meet Saracens on Saturday.
On Monday morning, Skosan, who scored 13 tries in 21 appearances in his first season at Saints, took to Twitter to express his feelings.
He wrote: "I would be lying if I said that it doesn’t hurt going out like that. A lot of mixed emotions, but will take all the learnings and come back stronger from this. Thank you for all the support this season & making me feel welcome at The Saints. God bless."
Saints supporters were quick to put a social media arm around Skosan, with plenty of them praising the wing's efforts this season.
Here are some of the responses…
Amanda Griffin (@amandagriff0504): Hold your head high and come back stronger, played some wonderful rugby this season and thoroughly entertained us.
Quick Whittington (@moglaven): You had a hard game on Saturday Courtnall, no doubt …but I’d reflect on all the good you have brought to our club this season, you’ve been a joy to watch
Chris Hood (@Chrishood57): There’s no escape now mate. You’re a Saint and will now forever be seen as a Saintsman. Already looking forward to next season’s fun and games. #COYS
Andy Yates (andy_ayates1): Your a joy to watch, everyone has off days - dont beat yourself up!. Can't wait for next season.. Enjoy Summer off with family!
Bex Kennedy (@becbec666): You’ve been exciting to watch this season and scored some amazing tries.!!! Yes Saturday was painful but that’s sport. But we’ll all be there cheering you all on again after your well earned break.
Dominic Newbould (@dominicnewbould): You helped get us there. Massive shift. Roll on next season
Tom Muzzy (@Tom_Muzzy_2001): You’ve been brilliant Courtnall. You’ve probably had the highest number of tries this season and you had a hat trick on your debut which was amazing. Keep your head up high and have a good summer.
Richard Bacon (@richard_bacon1): You’ve had an amazing season - the model of consistency tbh. Looking forward to seeing you back and even better for the experience next season.
Exiled_Sinner (@Exiled_Sinners): Don't beat yourself up, Courtnall. I have watched some of your games for Northampton and have been open-jawed at some of your speed & handling skills. Saturday will no doubt be a difficult game to watch back, but you guys fought your way to the playoffs. Go easy on yourself.
Stickman (@stick_man69): Could tell from your face at the end how much it stung. Sometimes the luck just isn't with you and dwell more in the excellence you've given to get us there from where we were just a couple of months ago. Enjoy the break and look forward to watching you tear it up again. #COYS
Mylerdoo (@Mylerdoo): It wasn’t to be. One heck of a run in from you and @SaintsRugby now go and enjoy some well earned time off
Joe O'Donoghue (@casualsaint): Great first season. Excited for more of the same next time
Teresa Watkins (@TeresaWatkins11): You have been sublime this season, enjoyed watching you play. Can’t wait for next season. Long may you be a saint
Chris Holmes (@ChrisHolmes31): Plenty of meat pies from you on debut season, can’t wait for next season. It’s only the start of the journey for the Saints . Enjoy your well earned break
Mr Breeze (@nickjamesbreeze): You've been amazing all season, any other day all of those would have stuck and we'd have been well ahead. Sport can be a cruel game at times. Enjoy the break
Iain (@Sparky_Iain): Ah thats sport, I wouldnt worry about it, enjoy the off season you have been superb this season. Come back better for it you have the pace and the skills back yourself everytime mate