's his strongest performance since the doors 
(ROOT (VP (VBZ 's) (NP (NP (PRP$ his) (JJS strongest) (NN performance)) (PP (IN since) (NP (DT the) (NNS doors))))))
(ROOT (VP (VBZ ) (NP (NP (PRP$ ) (JJS ) (NN )) (PP (IN ) (NP (DT ) (NNS ))))))