Having trailed 8-0 at the interval, Rhinos dominated the third quarter to go eight points clear, but soft tries from kicks on 76 and 78 minutes left the home team stunned.
Leeds played well for 20 minutes, but it wasn’t enough to end what is becoming a dismal run of results.
There were boos from the South Stand when the half-time siren sounded with Leeds trailing 8-0.
London were full value for that lead, having taken the sting – such as it was – out of Leeds early on and then scored all their points in the three-minute spell just before the half-hour mark.
It was the third time in their last seven halves of rugby Rhinos had failed to post a point, but they got back into it with a converted try immediately after the break.
This inspired a brief purple patch, but Leeds could not maintain it and London, aided by a late flurry of penalties, somehow rallied to snatch a win which didn’t seem possible with five minutes remaining and should never have happened.
To add to Rhinos’ woes, Adam Cuthbertson hobbled off in clear distress after suffering a leg injury early in the second half.
Nathaniel Peteru has been one of Leeds’ better performers in the pack this season and his strong run up the middle created a rare chance, for the horst on 11 minutes.
He was held down in front of the posts and Leeds took a tap, but the opportunity was wasted when Liam Sutcliffe couldn’t take Tui Lolohea’s pass.
Earlier, Konrad Hurrell had gone close without being able to get the ball away to his winger Ash Handley.
Rhinos did all the pressing in the opening quarter without being able to fashion any other chances and London went close to taking the lead when the ball was stripped one on one from Mikolaj Oledzki and Rhys Williams got over the line in the next set, but was held up by Leeds’ right-side defence.
The deadlock wasn’t broken until the 27h minute when London went ahead through a goal kicked by Kieran Dixon after Trent Merrin had been penalised for not clearing the ruck.
London got another penalty in the next set and following that Luke Yates got over the line, but was held up by Richie Myler and Matt Parcell.
On the next play, Jordan Abdull kicked to London’s left, it looked like the ball was going out of play, but Williams batted it back and Jay Pitts touched down.
It was a freakish try, but that sort of thing tends to happen to teams struggling the way Rhinos are.
Dixon converted and Leeds almost conceded again moments later when James Cunningham broke through and Abdull was in support, but was pulled down a blade of grass short of the line.
At the other end, Brett Ferres was held up by Alex Walker after Hurrell did well to get the ball away, but Leeds received two penalties deep in London territory in the final stages of the half and couldn’t find a way through, Jack Walker dropping Lolohea’s low pass when it seemed Rhinos had created an opening.
Leeds, despite the loss of Cuthbertson, looked sharper at the start of the second half and got back in the game on 44 minutes when Myler put on some footwork and jinked through from close to the line for a try which Lolohea improved.
That was Leeds’ first score since the ninth minute of last week’s defeat at Hull, a total of 115 minutes between points.
Liam Sutcliffe was held up over the line and Lolohea was denied in similar fashion after Rhinos tapped a penalty in front of the posts, which could have levelled the scores.
Leeds thought their attacking approach had paid off when Jack Walker stepped over from Lolohea’s pass, but referee Chris Kendall awarded Broncos a penalty instead for an obstruction.
That was the first of four successive penalties for London, which helped turn the tide.
Rhinos hit the front on 55 minutes with a quality score. Lolohea’s teasing last tackle kick was claimed by Tom Briscoe who offloaded to Sutcliffe and the back-rower suddenly found himself in space with support. Oledzki was next in line, which probably isn’t where he’d have chosen to be, but he held his nerve and passed on to Merrin who had the strength to power over for his first Rhinos try.
The conversion opened a four-point lead and Rhinos went two scores in front on the hour mark with another fine try on the last tackle.
Hurrell charged the ball in, Merrin and Lolohea kept it alive and Briscoe finished off, stepping past his opposite number Williams and stretching over. There was no goal, but suddenly Rhinos were playing as a team, with pace, confidence and creativity and it was good to watch but good teams maintain that sort of form and Leeds’ couldn’t.
The old problem of conceding soft penalties reared its head again and London were handed a way back.
Rhinos defended well for a while, but cracked with five minutes to go when Matty Fozard touched down from his own kick close to the line.
There was no conversion, but in the next set – after what seemed to be a London knock-on – Abdull kicked towards the posts, the defence failed to deal with it and Will Lovell touched down. That levelled the scores and Dixon’s conversion won it. Yet again, Rhinos could be aggrieved at some of referee Kendall’s decisions, but the fact is that’s an excuse – they should never have been in a situation where he had an effect.
Rhinos’ starting side was unchanged from last week’s defeat at Hull, but teenage prop Thomas Holroyd and veteran back-rower Jamie Jones-Buchanan came in on the bench in place of Brad Singleton and Brad Dwyer who were dropped.
It was 18-year-old Holroyd’s second senior game and the 413th Leeds appearance for Jones-Buchanan, 37.
Carl Ablett, who had been named in the initial 19, did not feature due to his on-going ankle problem and Kallum Watkins, Stevie Ward and Dom Crosby also remained on the casualty list.
Jones-Buchanan turned in a solid 44-minute spell and Holroyd looked strong when he came on for a brief spell in the final quarter. Holroyd’s inclusion was the first sign of coach Dave Furner losing patience with his senior players.
Three of last night’s 17 – Jack Walker, Harry Newman and Holroyd – are academy qualified. Eight of the Leeds team were on duty in the 48-32 middle-eights win at Ealing last August. London’s side included nine survivors from that game.
The penalty count finished seven-seven (four-three to Rhinos in the first half).
Rhinos under-19s take on London at Stanningley today (noon).