Clarke's goal nosed the hosts in front but a penalty from Aidan Carr, the son of Down manager Ross, on the stroke of half time gave the visitors a one-point lead.

Louth's stunning run of points, allied to a Lennon spot kick, gave them the Division 1B spoils.

Louth's first Division One outing since 2001 saw them begin in nervous fashion,and Down, bolstered by late inclusions Ronan Murtagh and Ronan Sexton, burst into a 0-4 to 0-1 lead.

Sexton (0-2), James McGovern and Dan Gordon all found their ranges for Ross Carr's men, who looked like getting in for an early goal only for Louth full-back Colin Goss to step in and deny them.

Clarke, who shot 1-5 in all, opened his account soon afterwards and Louth's charge gathered momentum as they grabbed 1-4, against Down's 0-2, over the course of the next 15 minutes.

Christy Grimes, Clarke (0-2) and Lennon traded points with Sexton and Aidan Burns as Louth levelled twice before notching their first goal.

Peter McGinnity began the move. He found Brian White, who sent in a diagonal ball, which was flicked down to the deadly Clarke, who made no mistake from close range.

Down may have led by 1-7 to 1-6 at the interval thanks to Carr's spot kick but, with Paddy Keenan and Mick Fanning taking over at midfield, the hosts upped the gear at the start of the second half.

Lennon grabbed three points. Aaron Hoey landed two and Keenan fired over an inspirational score as McEneaney's side roared into the lead after 12 minutes of fabulous football.

In reply, Down could only register a point from substitute Dan Hughes. Lennon won and then converted his penalty for a seven-point buffer.

Louth took their foot off the gas, and Down got back to within a goal of their hosts with points from Hughes, Benny Coulter, McGovern and Murtagh.

A Clarke free and another Keenan skyscraper was followed by a Barry Doran point as Louth, who face a daunting trip to Crossmaglen next Sunday, emerged four-point winners.

LOUTH: S Reynolds; D Brennan, C Goss, D Finnegan; J O'Brien, P McGinnity, R Finnegan; P Keenan (0-2), M Fanning; C Grimes (0-2), M Brennan, B White; A Hoey (0-2), S Lennon (1-3), D Clarke (1-5, 4f).

Subs used: D Reid for White (half-time), T O'Brien for M Brennan, JJ Quigley for Grimes (both 52 mins), J Doyle for Clarke (70).

DOWN: B Connell; K McGuigan, D Cunningham, P Shields; D McCartan, D Rooney, R Murtagh (0-1); B Coulter (0-1), J Lynch; R Sexton (0-3), A Carr (1-0, 1 pen), J McGovern (0-2, 2f); A Burns (0-2, 2f), D Gordon (0-1), M Poland.

Subs used: A Scullion for McGuigan (18 mins), M McClean for Lynch (half-time), D Hughes (0-2) for Poland (48), J Brown for Burns (52), B Doran (0-1) for Carr (55).

Referee: Jimmy White (Donegal).