Hasselbaink's men sealed a 2-1 win against Charlton to secure their first victory in four.
The Hoops won 2-1 as Matt Phillips and Nasser El Khayati scored either side of Jordan Cousins' goal for the Addicks.
But with the former Huddersfield stopper making an excellent save to deny Igor Vetokele shortly before the forward scored the stoppage-time winner, Hasselbaink suggested that it should be the man between the sticks that should be getting the plaudits.
"At times you need a bit of luck and your keeper to be smart. I must say that Alex Smithies won us the game today," he told Sky Sports.
"I am happy for Nasser but more happy for the team that we stuck at it, kept going, and in the end we finished them off even though we needed help from our keeper."
Although the club's play-off hopes are virtually over this season, Smithies' performance will give Hasselbaink plenty of optimism as he starts to look towards how they will get themselves into promotion contention next season.
Rob Green had spent several years as the club's number one but is reaching the twilight of his career and appears set for the Loftus Road exit in the summer (via Daily Mail), so the Dutchman would have wanted Smithies to shine as he looks to build for the future.
And with the 26-year-old putting in an excellent display against Charlton, the Rangers boss is likely to receive a confidence boost knowing that they are in safe hands with their new number one.