Leinster Rugby’s astonishing winning run continued on Monday, when they stretched the sequence to 12 in all competitions – but only just, as Munster Rugby were edged out 20-19 in the United Rugby Championship inter-provincial derby at Thomond Park.

Leinster, who head Pool A of the Heineken Champions Cup thanks to an overwhelming points difference, found their Pool B opponents a tougher nut to crack after Gavin Coombes cancelled out two Ross Byrne penalties with a converted try to give Munster a 7-6 half-time lead.

The home side were then awarded a penalty try after a yellow card for Leinster’s Max Deegan, but 14-man Leinster hit back with tries from Scott Penny and Dan Sheehan, which were improved by Byrne.

Patrick Campbell reduced the deficit to a single point with an unconverted try, but the runaway URC leaders hung on to stretch their lead at the top to eight points.

Meanwhile, Pool B team Ospreys registered a 34-14 bonus-point home victory over 14-man Scarlets, who had Tomas Lezana sent off in the fourth minute of the West Wales derby.

Alex Cuthbert, Luke Morgan, Rhys Webb, Sam Parry and Keiran Williams scored tries, Owen Williams kicked a penalty and two conversions, and Webb improved his own try as Ospreys recorded only their second URC win of the season.