Inconsistent Lynn's fightback fell just short as they were made to pay for a first-half horror show.

Hopes of building on Saturday's excellent 1-0 win at St Neots were blown away inside 20 first-half minutes as the Linnets shipped the same amount of goals as they did during their Walks wobble on Boxing Day against Kettering.

And while they at least made a fist of the second half – with Michael Clunan slotting a 70th-minute penalty and Lee Stevenson netting at the death – it was still a disappointing showing from a team that could have moved to within touching distance of the play-offs with a victory tonight.

The boos at half-time said all you needed to know about what the home faithful thought about the display as they were left pondering a simple question; How could this Lynn team play so well at the weekend yet misfire against opponents who had lost their last five matches and sat 19th in the Southern League Premier Division table going into the clash.

The pre-interval implosion began in the 17th minute when the referee's assistant on the far side did little to help the Jekyll and Hyde hosts' cause. Ryan Prosser looked at least five yards offside as he sprinted onto Ashley Evans' headed clearance but was not pulled up by the official and stroked home – much to the disgust of nearest defender Jordan Yong.

The blame for the Welsh club's second was internal as Lynn stood off Jon Brown and allowed him all the time in the world to swing in a cross, which was sidefoot volleyed home at the back post by an unmarked Ian Traylor.

Kayne McLaggon made it three by latching onto a Jarad Wright header in the 36th minute to heap more misery on the restless natives. They at least had something to cheer about as Clunan and Stevenson eventually registered, but by then the damage had been done.

Lynn: Street, R Fryatt, Gaughran (Castellan, 46), Miller, Yong, Clunan, Smith (Bridges, 5), Hurst, Stevenson, Friend (Mulready, 58), Zielonka. Subs not used: Pearson, Edge.

Merthyr: Clarke, Davies, Bloom, Evans, Jones, Baggridge, Jon Brown, Wright, McLaggon (Morgan, 78), Prosser, Traylor. Subs not used: Tancock, Jaye Brown.