Wagnerian aria andof Tristan and Isolde strangely enthralling live? (9)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

[Beginning of T ristan ISOLDE]* strangely with BE – live inserted. Didn’t we all know this? I suspect some Wagner buff will tell me this is an &lit. EDIT just checked on the web site and it seems to have the word pinnacle missing which would make it even harder.