As the two former Fulham and Blackburn Rovers managers faced off in the Midlands, Dorrans buried a 30-yard piledriver on 22 minutes - admittedly helped by slack defending from the visitors - as the hosts largely controlled the first half.
But QPR had their chances. Bobby Zamora was only kept out by some good goalkeeping from Ben Foster in the opening half, while in the second period the West Londoners had the best of the play, but were unable to find an equaliser.
The result sees the Baggies stay 13th, moving above Stoke City on goal difference but leapfrogged by Swansea City after their 3-0 win over Blackburn put them a goal ahead of Roy Hodgson’s side.
QPR, meanwhile, stay 16th, two points clear of the relegation zone and likely to be dragged into the relegation scrap if Bolton Wanderers win their two games in hand.
West Brom had more possession and opportunity but the visitors were dangerous on the break, particularly through Zamora, who had the first chance of the match when he was denied by Foster’s smothering save in the second minute.
The Baggies responded when the recalled Peter Odemwingie flashed a low effort across goal but wide, and they took the lead midway through the half as Dorrans announced his return to form.
It was some goal too, the Scottish midfielder firing a superb long-range drive into the top left corner, although he was helped by terrible defending from QPR, who backed off to allow him plenty of time and space to fashion the strike.
The pattern of Baggies possession and Hoops counters continued, with Samba Diakite firing into the side netting after excellent play by Joey Barton on the right, Barton involved again when his delightful scooped cross was met by a flying Zamora, who headed just wide.
Zamora was in the thick of the action and was denied a spectacular goal by heroic keeping from Foster, the former Fulham striker killing Taye Taiwo’s long ball with a superb first touch before unleashing a half-volley with his second. The Baggies keeper made himself big to deny the sometime England international.
QPR upped the ante in the second half, taking their turn to control possession as West Brom sat increasingly deep.
However, they actually created fewer chances than in the first period, a lack of final ball from the likes of Adel Taarabt and Shaun Wright-Phillips leaving Zamora and substitute Heidar Helguson somewhat isolated.
Indeed, the Baggies actually looked more dangerous on the break, as attacking full-back Billy Jones hit the post, while Clint Hill denied sub Shane Long with a fine saving tackle and Chris Brunt’s free-kick was well saved by Paddy Kenny.
QPR, for their part, only managed a mis-hit finish by Zamora: indeed, the hosts should have added a second deep into injury time when Long skewed a finish wide with just Kenny to beat, although the Ireland striker felt he had been impeded by Nedum Onuoha.
The visitors huffed and puffed to the final whistle, Hughes clearly frustrated with his side’s lack of cutting edge, as the Baggies effectively ensured their safety with four matches remaining.