Salford (14) 17
Tries: Smith, Swain Goals: Holdsworth 4
Harlequins (4) 14
Tries: Purdham, Jones-Bishop 2 Goals: Orr Drop Goal: Smith
Danny Holdsworth has now kicked 40 goals this season for Salford City Reds
Salford held on to claim their first double of the season as they again earned a narrow victory over basement rivals Harlequins at The Willows.
After winning 26-22 at The Stoop in March, this time it was even closer after Quins fought back from a 16-4 deficit with half an hour to go.
Two second-half tries from Ben Jones-Bishop made it interesting.
But Daniel Holdsworth's kicking proved the key to victory, with two penalties to add to two first-half conversions.
Salford's two first-half tries came from Matty Smith, who rounded off his side's scoring with a late drop goal, and Luke Swain.
Skipper Rob Purdham went over for the visitors in between Salford's two tries.
With both clubs locked together on 10 points in 12th and 13th respectively, victory was a must if either were to persist with faint play-off aspirations. But it was Salford who eventually came through a closely-fought contest to claim only their sixth win of the season - and move within five points of the top eight.
Quins, who lost scrum-half Chad Randall with a dislocated shoulder, edged the opening exchanges only for Salford to score on their first meaningful venture downfield in the 10th minute.
The dangerous Holdsworth scooped the ball from dummy-half, drew in the Quins defence, and his killer, delayed pass sent Swain in for his first try of the season.
Holdsworth duly converted, but Purdham responded for the visitors just four minutes later when Tony Clubb managed to resist tackles from Ashley Gibson and Karl Fitzpatrick before offloading for his captain.
After Danny Orr had put his tricky conversion attempt wide, Salford went further ahead on 22 minutes when another masterly pass from Holdsworth created Salford's second.
The Australian playmaker delayed just about long enough for the fast-moving Smith to take the ball against the grain, rounding Luke Dorn on his way to the line.
Holdsworth again converted, adding his first penalty, while Quins winger Jamie O'Callaghan had a score chalked off for knocking on just before the interval, which came with Salford 14-4 up.
After one miss, Holdsworth's fourth goal of the evening put the hosts further ahead on 47 minutes.
But, after some determined Salford defence, Quins finally scored again on 58 minutes through Jones-Bishop, switched from full-back to centre in only his second game back after injury.
Clubb drifted harmlessly along the 40-metre line before eventually straightening up, his one-handed ball unleashing Jones-Bishop, who put his foot on the gas, coasted past Tyrer and then snaked his way over for a try converted by Orr.
Karl Fitzpatrick then came up with a fantastic try-saving tackle on Luke Dorn, only for Smith to drop a goal seven minutes from time which stretched Salford two scores clear.
Jones-Bishop's second score in the closing stages just a minute later, Orr missing the conversion, made for a very nervy finish but the home side held on.
Salford coach Shaun McRae said:
"If you're talking about defending your own line, showing determination, grit and steel and all those things then I thought we were very good.
"At 14-4 at half-time you're one score from winning comfortably but they were able to come back at us and it was pretty nervy for a while.
"We've played better and won games, but we've played better and lost games too.
"It was a scrappy game but my theory on that is that we came into the game having played St Helens and Harlequins having played Wigan and both sides were tired.
Harlequins coach Brian McDermott said:
"I thought we played very well and defended very strong.
"We had a couple of defensive blips near our try-line early on and I don't think they really challenged our line at all in the second half."
"It was a big hit on Chad Randall. He's dislocated his shoulder. We weren't able to put it back in in the dressing room afterwards."
Salford: Fitzpatrick, Broughton, Henry, Gibson, Tyrer, M Smith, Holdsworth, Boyle, Alker, Leuluai, Sibbit, Littler, Swain.
Replacements: J Smith, Sidlow, Adamson, Parker.
Harlequins: Dorn, Sharp, Clubb, Jones-Bishop, O'Callaghan, Gale, Randall, Ward, Ellis, Temata, Purdham, Melling, Wilkes.
Replacements: McCarthy-Scarsbrook, Mills, Orr, Golden.
Referee: Phil Bentham (Warrington)