Saints went to Loftus Road just one place and one point better than Mark Hughes's bottom-of-the-table side, but the gulf in class on display was stark.
Saints boasted a deserved two-goal advantage at half-time courtesy of efforts from Rickie Lambert and man-of-the match Puncheon and, while Junior Hoilett reduced the deficit, Anton Ferdinand put into his own goal to secure a 3-1 win for the visitors.
Success was sweet for Puncheon having spent an unsuccessful loan spell with QPR last season, but he was more pleased that Southampton were able to show what he feels to be their true ability in west London.
"It's always good to get one against a former club, but the most important thing was getting three points," Puncheon said. "We sort of got on the front foot and did what we've been doing in recent weeks
"I thought we were solid, and that showed in the first half and the second half. We have always known as a group that we shouldn't be where we are. There have been games that haven't gone our way and games that have slipped through our hands, but we were determined not to do that from back-to-front and in (terms of) finishing off goals and that happened."