Leinster missed the chance to extend their lead at the top of the Vodacom United Rugby Championship after suffering a 44-12 defeat to Emirates Lions at Emirates Airline Park.
The Irish province, who last week booked their place in the Investec Champions Cup semi-finals after eliminating holders La Rochelle, had won 11 of their last 12 matches in the competition.
But, having made 13 changes, Leo Cullen’s side was blown away inside the opening 15 minutes as three Lions tries put them on the way to a victory which boosted their play-off hopes.
Leinster are now just one point clear of Glasgow Warriors with four rounds remaining while the Lions climbed into the top eight.
The Lions made a stunning start and grabbed the opening try inside 40 seconds as Richard Kriel and JC Pretorius combined to send Morne van den Berg in under the posts, with Sanele Nohamba converting before kicking a penalty seven minutes later.
A fantastic team try saw the Lions score again in the 10th minute, Francke Horn, Van den Berg and Marius Louw were all involved before the latter cruised over but Nohamba was unable to add the extras.
It went from bad to worse for Leinster three minutes later as Nohamba pounced on a loose ball before putting Quan Horn through, which the former converted for a 22-0 lead.
Leinster pair Liam Turner and Cormac Foley had tries disallowed for a knock-on and forward pass respectively either side of the break before Nohamba’s penalty extended the Lions’ lead.
The Irish side finally got on the board in the 53rd minute when Ciaran Frawley pounced on a grubber kick from Harry Byrne, who added the extras.
But moments later the Lions secured the bonus point when Emmanuel Tshituka went over after loose play from Leinster but Nohamba could not convert.
Frawley claimed his second try following some slick passing from Leinster but Byrne missed his kick to leave the score 30-12.
Tshituka and Francke Horn added further tries in the final five minutes, both converted by Jordan Hendrikse, to cap an excellent day for the Lions.
Scorers:
Emirates Lions: Tries: Morné van den Berg, Marius Louw, Quan Horn (2), Emmanuel Tshituka (2). Conversions: Sanele Nohamba (4). Penalties: Sanele Nohamba (2).
Leinster: Tries: Ciarán Frawley (2). Conversion: Harry Byrne.
Teams
Emirates Lions: 15 Quan Horn, 14 Richard Kriel, 13 Erich Cronje, 12 Marius Louw (c), 11 Edwill van der Merwe, 10 Sanele Nohamba, 9 Morné van den Berg, 8 Francke Horn, 7 Emmanuel Tshituka, 6 JC Pretorius, 5 Ruan Delport, 4 Willem Alberts, 3 Ruan Dreyer, 2 PJ Botha, 1 Morgan Naudé. Replacements: 16 Jaco Visagie, 17 JP Smith, 18 Asenathi Ntlabakanye, 19 Reinhard Nothnagel, 20 Sibusiso Sangweni, 21 Nico Steyn, 22 Jordan Hendrikse, 23 Henco van Wyk.
Leinster: 15 Ciarán Frawley, 14 Rob Russell, 13 Liam Turner, 12 Charlie Ngatai, 11 Andrew Osborne, 10 Harry Byrne, 9 Luke McGrath, 8 Max Deegan, 7 Scott Penny (c), 6 Diarmuid Mangan, 5 Jason Jenkins, 4 Brian Deeny, 3 Thomas Clarkson, 2 Lee Barron, 1 Cian Healy. Replacements: 16 John McKee, 17 Michael Milne, 18 Michael Ala’alatoa, 19 Ross Molony, 20 Rhys Ruddock, 21 Cormac Foley, 22 San Prendergast, 23 Ben Brownlee.