The Dons sit second in the table – just two points behind unbeaten Barrow – and have not lost since the opening day of the season.
But they needed a last gasp try to rescue an 18-18 draw at Hunslet and then started slowly at Coventry last weekend before running out 34-16 winners.
Horne says tight games are the perfect preparation for the play-offs but accepts that his side will have to bring their A-game to get the better of Barrow.
“Last week at Hunslet was play-off rugby,” said Horne.
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“Those sort of games are good preparation and it allows us as staff to have a look at them and assess and see where we went wrong and build for those play-off games.
“Being in tight games is good preparation but we need to be improving each week in what we’re doing.
“We’ve sort of levelled off a little bit in the progression that we’ve been making so hopefully this week’s a really big week for us training-wise going into Barrow.
“It’s a really big game for us.”
A strong second half performance saw the Dons come from 16-12 down at half time to beat a spirited Coventry side.
But Horne was left concerned about the way his side started and also questioned his players’ mentality going into the game.
“We found a way to get ourselves back into the game and kick on and go and win it,” said Horne.
“There’s signs of really good spells in the game but just not quite as much as we’d like.
“It was good to get the response that we wanted but against Barrow we can’t afford to be starting like that. They will punish us with the quality that they’ve got within their squad.
“The boys have shown a lot of determination over the last five or six weeks and it’s something we keep building on.
“We just have to be a lot smarter and more mentally prepared. I don’t think we gave Coventry enough credit judging by the way we started the game and it nearly cost us.”