“You’re the only one with enough experience to do this incredibly difficult work”, then come review I get “underperforming”???

Got an underperforming on review after doing something supposedly no one else on the team could do. It was given to me after no one else was able to solve it. It took a while but I got it done and they thought it might not be possible, and saved the company tons of effort Anyway… time to start the job search