A youthful Leinster team maintained their BKT United Rugby Championship table-topping form with a 38-14 win over Cardiff at the RDS.Luke McGrath scored two tries in a 10-minute spell, adding to Max Deegan's opener, as Leo Cullen's much-changed side led 19-0 at half-time.Cardiff struggled to get going in greasy conditions, a Jason Harries yellow card being swiftly followed by Brian Deeny's 49th-minute bonus-point score.Cardiff had two late scores from replacements Rory Thornton and Kristian Dacey, in response to a Max O'Reilly effort, but the hosts had the final say when Liam Turner capitalised on a loose pass from Ellis Bevan.Despite the returning Rey Lee-Lo landing a thumping tackle on Harry Byrne, Leinster took a sixth-minute lead through their industrious forwards.Having been held up short moments later, number eight Deegan powered over for an unconverted try following John McKee's tapped penalty and an inviting pass from Scott Penny.Max Deegan's early try has Leinster in front against Cardiff