Leinster Rugby sewed up top spot in Guinness PRO14 Conference B and a home semi-final with a 19-7 win over the Toyota Cheetahs at the rain-hit RDS.

The defending champions sealed a table-topping finish with four rounds still to play, building a 12-7 interval lead against the South Africans. Conor O’Brien and the prolific Sibahle Maxwane swapped tries during Ox Nche’s sin-bin period inside the opening quarter, and Adam Byrne marked his 50th Leinster cap with a well-taken effort in the corner.

Rory O’Loughlin’s smartly-finished 55th-minute try from his own chip kick opened up a 12-point cushion and that is how it stayed, their 15th victory in 17 rounds leaving the province a full 26 points clear of second-placed Benetton Rugby.

The early kicking battle was broken up by prop Nche’s ninth-minute sin-binning, which saw him catch Fergus McFadden with a late shoulder charge. Leo Cullen’s men immediately took advantage, mauling up close before big centre O’Brien powered over to the left of the posts for Ross Byrne to convert.

Maxwane’s searing pace turned a hack downfield by Benhard Janse van Rensburg into the flying winger’s 13th try of the PRO14 season, with Tian Schoeman’s conversion bringing the visitors level. Leinster retook the lead early in the second quarter, winger Byrne fed by O’Loughlin’s long pass and he stepped inside Maxwane’s tackle and got the ball down under pressure from Louis Fouche.

The remainder of the first half was rather listless with the Cheetahs sticking to their tactical kicking and Leinster unable to get back into scoring range, despite promising runs from Max Deegan, the eventual man-of-the-match, and captain Rhys Ruddock near halfway.

Ireland prop Andrew Porter leaked two penalties after his 43rd-minute introduction, but his lineout infringement went unpunished with Schoeman pushing his kick wide from the right.

Leinster got the scoreboard moving again approaching the hour mark, the Cheetahs defending the maul threat initially but O’Loughlin chipped over the top, dinked the ball on further and won the race to the touchdown. Out-half Byrne added a well-struck conversion from the left.

Replacement Porter’s impressive penalty win at the breakdown repelled Franco Smith’s side, and Deegan stood out in the closing stages with a brilliant tackle on Schoeman which forced a knock-on and a lineout steal in his own 22. Leinster ended the game hunting for a bonus point score through their forwards but the Cheetahs held them at bay.