The names of the festivals in Olympia and Delphi are not mentioned by Pausanias, but are very clear from the context:
'τετράκις γὰρ δὴ ἐν ἀνδράσι κατεμαχέσατο ὁ Τίσανδρος πύκτας ἐν Ὀλυμπίᾳ, τοσαῦται δὲ καὶ Πυθοῖ γεγόνασιν αὐτῷ νῖκαι, Κορινθίοις δὲ οὐκ ἦν πω τηνικαῦτα οὐδὲ Ἀργείοις ἐς ἅπαντας ὑπομνήματα τοὺς Νέμεια καὶ Ἴσθμια νικήσαντας.' ('For Tisandros won the boxing match in the category for men four times at Olympia, and there were as many victories for him in Pytho. But the Corinthians nor the Argives kept records at all at this time of all those victorious at the Nemea and the Isthmia.').
It is however not clear whether Tisandros competed at the Isthmia and the Nemea, wherefore Farrington marks him a doubtful Isthmionikes.
Comments by DL:
Pausanias mentions the four Olympic victories of Tisandros (as well as four Pythic victories). He adds that the Nemea and Isthmia did not keep victory lists yet, implying that Tisandros had also won victories at these festivals. The Nemea were first held in 573 BC (Moretti 1957, no. 94) and after 500 BC we know about most Olympic victors in pugme. Also the fact that Pindar mentioned Tisandros suggests a certain antiquity of Tisandros' victories. Hence, the dating around the mid-6th century BC, following Moretti 1957, no. 94. Moretti suggests the victories to have taken place at the 52nd, 53rd, 54th and 55th Olympiads (572, 568, 564 and 560 BC).