Adrian Cieslewicz's first-half strike gave Wrexham victory in the Welsh derby against Newport County at Spytty Park.
Wrexham's winner came in the 10th minute with the Polish midfielder shooting from inside the 18-yard box.
Newport, who are safe from relegation, dominated territory in the second-half in what could be their last game at Spytty but Wrexham held on for victory.
Wrexham, who made eight changes to the side, have one more regular season game at home to Braintree on Saturday.
Second-placed Wrexham still do not know who they will face in the play-off semi-final. It could be Luton, York City or Kidderminster.
Newport now have one league game remaining at Barrow on Saturday before their FA Trophy final appearance against York City on 12 May.
VIEW FROM THE DRESSING ROOM
Wrexham player-manager Andy Morrell told BBC Radio Wales:
"The pitch was unbelievable. How they have played 23 games there I will never know and got through the season.
"The lads gave it everything. Second-half was tough but they [Wrexham] defended really well.
"There's a lot of positives. They have stood up and been counted."
Newport manager Justin Edinburgh told BBC Radio Wales:
"I'm always disappointed to lose any game. In all honesty our final ball and pass let us down in the final third.
"It's a tough pitch to play on but both teams gave a good account of themselves on it but it's very difficult at times.
"Lots of positives. My players have given everything in terms of effort and commitment."