Doncaster RLFC posted their fifth successive League One win as they completed a double London Skolars at the Keepmoat.
But the Dons flattered to deceive on the day and had to work far harder for their scrappy 38-6 win they had done when beating Skolars 42-18 in the capital in May.
The fifth-placed home side had looked set to run up another big win over a London side in danger of finishing in their lowest placing in several years when scoring three early tries to lead 16-0.
But as mistakes started to creep into Doncaster’s game, London came more into the frame in the second quarter and were still in contention at the break.
Things didn’t get much better - for what looked to be the club’s lowest league gate of the season - in the second half and a couple of late tries served to paper over the cracks.
The Dons opened the scoring on four minutes - leading try-scorer Jason Tali handing off a defender ten metres out to score near enough for Matty Beharrell to convert via the far post.
The home side continued to make the early running and dual-registered full-back Hakim Miloudi sent winger Richard Owen in from close range on eight minutes after squeezing the ball out of the tackle as the London cover tried to force him into touch.
Miloudi then shot through a gap inside the London 20 following some more snappy handling. Beharrell added the extras to make it 16-0 after just eleven minutes.
Little had been seen of Skolars in attack in the first quarter but they would have opened their account three minutes into the second but for Miloudi denying winger Billy Driver just short of the line after he had got past Beharrell.
Skolars weren’t to be denied, however, and powerful winger Lameck Juma touched down for a converted try two minutes later.
The Dons struggled to recapture their earlier sparkle until centre Jack Logan rounded off some neat handling when cutting in from close range to score an unconverted 32nd minute try to make it 20-6.
Kicks meant for Owen by Jez Litten and Beharrell deserved a better outcome.
The home side were slow to get into their stride after the break and with never-say-die Skolars playing with plenty of spirit there was little to choose between the two sides in the third quarter.
The Dons, who always had more of a cutting edge, finally extended their lead on 54 minutes when prop Connor Scott forced his way over from close range for a try converted by Beharrell.
The Dons bombed a gilt-edged chance on 69 minutes with Miloudi - who seemed in two minds what to do – coming in for some criticism from team-mates.
Hooker Kyle Kesik’s determination saw him reach and get the ball over the line in the 76th minute.
Logan held off the cover on a long run for a last minute try again converted by Beharrell.
Dons: Miloudi, Sanderson, Logan, Tali, Owen, Howden, Beharrell; Scott, Kesik, Spiers, England, Mariano, Martin. Subs: Osbourne, Muranka, Hedges, Litten.