Was number 4 in Portugal and Spain after song was devastating (8)

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

WAS + fourth letter of [por] T [ugal] + E (abbreviation for Espana = Spain), all after LAY (an old word for a song). I’m not sure the grammar is quite right in the definition. Surely “lay waste [to . . .]” is present tense, and the past tense (required by “was devastating . . .”) would be “laid waste to . . .”? But perhaps there’s a construction I’ve missed.