diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 5d2fd52..fa9d652 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -166,6 +166,7 @@
 
 void perf_session__remove_thread(struct perf_session *self, struct thread *th)
 {
+	self->last_match = NULL;
 	rb_erase(&th->rb_node, &self->threads);
 	/*
 	 * We may have references to this thread, for instance in some hist_entry