Lansdowne guaranteed their presence in the Energia All-Ireland League Division 1A semi-finals with a 52-21 home victory over UCC.
Mark McHugh's men had the bonus point tucked away by half-time with lively fullback Eamonn Mills bagging a brace, but the concession of three maul tries was a concern.
UCC, who are destined for the relegation play-off, hit the front when hooker Tadgh McCarthy crashed over from an early lineout drive. Daniel Squires converted.
However, Dan Murphy crashed over for an 11th-minute leveller and Lansdowne's backs were in lethal form with Mills (twice), Michael Silvester and replacement James Reynolds all touching down.
Clontarf sealed a home semi-final after defeating Cork Constitution 24-12 at Temple Hill in business-like fashion.
A dominant set piece and tries from Tony Ryan, Michael Brown and Cian O'Donoghue set 'Tarf up to beat the defending champions who are still hanging on to the last play-off spot.
After O'Donoghue's 56th-minute intercept try, Con returned fire with an intercept effort from Munster's Alex McHenry, past the hour mark, and flanker John Forde touched down in the 78th minute. However, it was too little, too late.
Dublin University are right back in the play-off picture after picking up their second successive victory, winning 30-19 at Ballynahinch. Flanker Alan Francis impressed with a brace of tries.