Cumbria's Stuart Lancaster admits Leinster still have plenty of work to do.

Leinster moved six points clear at the top of Champions Cup Pool 3 on Sunday with a 18-8 win at Exeter.

But it was the try scored by Exeter’s James Short which frustrated the former England coach, from Culgaith, near Penrith.

“I know we’ve got plenty to work on because we conceded a try that still frustrates me now even as I think about it,” said the 48-year-old.

Asked what went wrong in the build-up to Short’s try, Lancaster said: “A catalogue of things really.

“Little things we know how to fix. I was disappointed we conceded it but, overall, I’m delighted with the performance.”

Johnny Sexton will not train until later in the week, although the Irish club insist he will be available for selection in Saturday’s return leg.

Meanwhile, Rhys Ruddock is out for the foreseeable future with a hamstring injury.

“Rhys will be a while,” Lancaster confirmed to The Irish Times .

“We won’t have him in the next few weeks certainly. We’re optimistic about Johnny.”

And the Penrith-born senior coach also praised flanker Dan Leavy, saying he has now entered “the world-class category”.

“He’s playing at the top of his game and that takes him into a world-class category,” he said.

“But we’ve got to give Ross Byrne and Joey Carbery great credit.

“Particularly Ross, I thought him and Jamison Gibson-Park were really composed in seeing out the game when Johnny came off.

"And Isa Nacewa had to kick the goal. But Johnny is a key man, he’s not only playing well, he is, most importantly, leading.”

Lancaster, who has been linked with the vacant Northampton Saints rugby director position, was England coach from 2012-2015. He joined Leinster last year.