Danny Carroll headed a late goal to give Crawley another three points in their quest for promotion to the Conference.

Carroll headed in Ben Judge's right-wing cross six minutes from time to earn Billy Smith's side a victory that maintains their four-point lead at the top of the Dr Martens premier division.

The goal capped a spirited fightback from the home team who trailed 1-0 at the break.

Carroll said: "I kept saying to the lads if I got one more chance I'd score. I had five or six, and hit the post and the bar. It sounds selfish but I felt I should have had a hat-trick."

But he was not too unhappy.

"I normally get 15 goals a season and I've got 11 already so I'm well on course.

"We got the win we needed and some of the other chasing teams dropped points. If we keep winning that puts more pressure on them."

With his side losing 1-0 with 30 minutes left, Carroll and Smith agreed the turning point came in the 57th minute when Dave Harlow and Lee Doherty came off the bench to replace the midfield duo of Luke Anderson and Jimmy Dack.

The double substitution seemed to galvanise Crawley. Doherty allowed Judge to push up into midfield and Harlow started to orchestrate proceedings in the middle of the pitch.

Carroll said: "Dave Harlow started passing the ball around and we committed more men forward. We had a bit of luck with the equaliser but I felt we thoroughly deserved the win."

Merthyr, managed by former West Ham striker Leroy Rosenior, capitalised on Steve Restarick's profligacy in front of goal to take the lead with a classic sucker punch after 32 minutes.

Nigel Brake crossed from the left and Restarick was unable to turn the ball in from close range, allowing the visitors to break and Paul Hunt burst through the middle to loft the ball over Andy Little.

After the break, Ben Abbey and Carroll spurned good opportunities and Crawley were indebted to a huge piece of luck for their equaliser.

Jay Lovett crossed from the right and the Welsh side's captain and goalkeeper, Neil Thomas, looked certain to make a comfortable catch but the ball squirmed through his hands and across his line.

The goal was harsh on Thomas, who until then, looked the only thing between the Reds and an equaliser.

Crawley sought to capitalise on their good fortune and pounded the visitors' goal.

Ian Payne had a shot tipped over by Thomas and substitute Rob Collins threaded a tantalising ball across the face of the goal.

With six minutes remaining, the league leaders finally took the lead when Judge jinked his way past two defenders and crossed to Carroll who powered in.

Collins nearly made it 3-1 but his angled drive cannoned off Thomas' right-hand post.

Smith was satisfied, even though it was not a "vintage" performance. The Crawley boss also admitted Carroll can be a role model to his other midfielders.

Smith said: "Danny took his goal well and hit the post too. He gives himself a chance because he gets in the box. He is different to the other players.

"I've said to Luke (Anderson, the captain), and Jimmy Dack, you don't give yourself a chance to score because they are not getting in the box enough.

"Danny turns up in the box and that's where you get goals. In the second half we got more men in the box.

"We haven't got a big centre forward so we have to play the ball on the ground and get around the back."