Derry City took full advantage of Shelbourne dropping points as they secured a vital 1-0 win away to Waterford.
A goal from Ben Doherty in the 60th minute gave Derry the win to put them top of the table on goal difference, ahead of Shelbourne.
Damien Duff's side were held to a 1-1 draw at home to Bohemians.
Danny Grant gave Bohemians the lead after 12 minutes, but Shelbourne responded just two minutes later through Ali Coote.
At the other end of the table, Drogheda United recorded a resounding 7-0 win at home to Sligo Rovers.
Drogheda were 2-0 up through Andrew Quinn and Douglas James-Taylor after just 11 minutes. They took a 3-0 lead into the interval through Frantz Pierrot in the 37th minute.
Pierrot added a fourth, before Conor Kane made it five just after the hour mark.
Elicha Ahui made it 6-0 and Adam Foley completed the scoring with the seventh as Drogheda moved off the bottom of the table in style.
Dundalk drop to 10th, and will not play this weekend after their game against St Patrick's Athletic was postponed due to St Pat's involvement in the Europa Conference League play-off next Thursday.
Dundalk manager Jon Daly has described the decision to postpone Sunday’s Premier Division game with St. Pat’s as farcical.
The FAI made the decision based on what they’ve described as the Saints’ exceptional circumstances in Europe.
Last night’s scoreless draw with Istanbul Basaksehir means Pat’s are potentially 90-minutes away from a Conference League group place.
