New England Whalers Captain Ted Green pouring champagne or beer over his head while Tim Sheehy looks on.

Whalers dressing room in Boston Garden on May 6, 1973.
New England had defeated Winnipeg Jets in game 5 to win the Avco Cup in 5 games.

The Avco World Trophy / Avco Cup was not ready for presentation, so the WHA league apparently quickly purchased a $20 trophy from a local Boston Sports store to present to the Whalers, which is the trophy you see in this photo.
Differing sources stated that Green and his teammates were presented with the Eastern Division championship trophy.