At a wet and windy Lakelands, Terenure struggled to cope with Lansdowne's pace and power as well as the wintry conditions. 'Nure were 15-0 down following McCarron's first two efforts and two successful kicks from full-back David Hewitt.
The players and match officials had to leave the pitch for ten minutes, early in the second half, due to lightning overhead. In the end, a David McAllister penalty was all the hosts could muster and Lansdowne, with scrum half Matt Healy again in fine form, put the result beyond doubt with McCarron's hat-trick score.
At the other end of the table, Dublin University, Malone and Old Crescent are all still winless after their four outings of the league campaign.
Trinity have come very close to breaking their duck in recent weeks, but luck had not been on their side. This weekend, Clonakilty edged them 9-6 in a closely-fought game at Shannonvale Cross.
A last minute penalty from Kurt Morath rescued the points for Clon, who faced into a strong wind in the first half. Trinity out-half David Joyce had given his side a 6-0 interval lead with two successful penalties, but it was not enough in the end.
Malone were left licking their wounds after a disappointing 18-3 defeat to Greystones at Dr. Hickey Park. It was a case of the old and new coming to the fore for 'Stones, with experienced centre Barry Lynn landing six penalties and winger Andrew Kealy making an assured AIB League debut.
There was no joy for Old Crescent out west as Corinthians picked up their third league win, emerging as 36-15 victors over the Limerick men.
The sides shared out seven tries in an open, free flowing game. Crescent had the wind advantage in the opening half and struck for the opening try when out-half Mark Woods blitzed through the Corinthians cover and sent winger Marcus O'Connell over for an unconverted score.
Just three minutes later, Crescent captain Mark Ryan cleaned out a lineout close to the Corinthians whitewash and dived over for an opportunist seven-pointer.
The visitors added a penalty and almost got over for a third try on the stroke of half-time, but Corinthians held out and the second half proved to be a fruitful one for them.
Turning things around, the Galway outfit notched two tries while Ryan was in the sin-bin. Scrum half Mick Roche finished off some good foraging by the home pack and then centre Eoin Griffin sniped through for the second, with out-half Bayden Morey converting both for a 15-12 scoreline.
Roche passed for onrushing full-back Darin Claasen to score in the corner and nudge Corinthians ahead, and a late brace of tries from livewire flanker Liam Carpenter confirmed a memorable comeback win for the Eugene Murnane and Sean Duignan-coached home side.
Thomond are now on their own in second place after fighting back to earn a share of the spoils with Highfield at Liam Fitzgerald Park. The Munster rivals played out an entertaining 26-26 draw, with goalkickers Declan Cusack (Thomond) and Colin Mahony (Highfield) kicking two conversions and four penalties apiece.
The try scorers for the home side were Daragh O'Neill and Warren Kelly, while Michael Knowles and David Kelly both touched down for 11th-placed Highfield.
Old Wesley got back to winning ways as they overcame a 9-0 half-time deficit to secure a 20-12 victory over a previously unbeaten DLSP side at Kirwan Park.
South African scrum half Dustin Jinka kicked three penalties to give a territorially dominant 'Salmo a decent lead, but Wesley took over in the second period and dictated play for long periods, with their hard-working back row unit of Greg Jacob, John Carroll and Richie Murphy getting on the ball time and again.
Full-back Brian Doherty crossed for the visitors' first try, capitalising on a well-weighted crossfield kick from out-half David Smith, who also added the conversion.
A Smith drop goal on the hour mark sent Wesley ahead and he followed up with a successful penalty, although Jinka replied for DLSP with his fourth penalty to set up a grandstand finish.
The decisive score came in injury-time when centre Michael Hastings intercepted a pass in midfield and last season's Division 3 play-off champions countered well before Murphy was given enough room to score close to the posts. Smith's pinpoint conversion robbed DLSP of a losing bonus point.
Bruff's 24-12 defeat of UCD at Kilballyowen Park has vaulted them up to sixth in the table. Team captain Brian Cahill kicked a penalty and converted tries from Gary Leonard, Nigel Riordan and Patrick Thompson.
UCD were visiting Bruff's home ground for the very first time and edged ahead on the scoreboard when out-half Niall Earls kicked the first of his four penalties. But the students struggled to use the blustery wind to their advantage and Bruff hit back with a late try.
Brian Cahill carved open the UCD defence on a slashing run and he popped the ball inside for centre Leonard to cover the final metres to the line. Bruff put some daylight between the sides, four minutes into the second half, when winger Riordan broke through for a converted try.
Three quick-fire penalties from Earls clawed it back, UCD then missed a gilt-edged chance to score a breakaway try and Bruff, having survived a sin-binning, showed great resilience to close out the game in injury-time.
Full-back Thompson gobbled up a loose ball just inside the hosts' half and dashed all the way in under the posts for Cahill to add an easy conversion and leave UCD out for the count.
Meanwhile, Belfast Harlequins fell to their first defeat in this season's league, going down 24-23 to a fired-up Bective Rangers side at Donnybrook.
'Quins' 10-0 lead, following a try from Miles O'Hagan and two successful kicks from Ireland 'A' international Niall O'Connor, was erased by two Cormac O'Beirne penalties and a 29th minute try from winger Mike Smith, which out-half O'Beirne set up with a long skip pass.
Two further penalties from O'Beirne, the second coming after 'Quins centre Michael Allen was red carded for a dangerous challenge, moved Bective further ahead, before O'Connor made it 17-13.
A penalty try gave the hosts some breathing space at 24-13 but 'Quins have to be commended for launching a late fightback which earned them a bonus point. O'Connor's 69th minute penalty was followed by a well-taken injury-time try from scrum half Michael Heaney.
AIB LEAGUE DIVISION 2 RESULTS: Saturday, October 31
Bective Rangers 24 Belfast Harlequins 23, Donnybrook
Bruff 24 UCD 12, Kilballyowen Park
Clonakilty 9 Dublin University 6, Shannonvale Cross
Corinthians 36 Old Crescent 15, Corinthian Park
De La Salle Palmerston 12 Old Wesley 20, Kirwan Park
Greystones 18 Malone 3, Dr. Hickey Park
Terenure College 3 Lansdowne 23, Lakelands Park
Thomond 26 Highfield 26, Liam Fitzgerald Park