Back in part I (keeping the whole double agent Itachi thing in mind) Kisame was hesitant on confronting Jiraiya knowing he had Itachi on his side (who dealt with Orochimaru easily by himself). I know that Itachi was hyping him up to avoid combat, but in Kisame's perspective those two should have been able to handle Jiraiya. Hell, i think in Part II Sasori (assuming by himself since Deidara had no knowledge of their upcoming meeting) was prepared to face Oro when he was going to meet Kabuto on the Tenchi Bridge.