Earlier, Sheffield United surrendered their lead at the top after a 2-0 home loss to fellow promotion-rivals Burnley.
Josh Brownhill (43rd) and Zian Flemming (53rd) scored to shock the Blades on Thursday, with Socceroos and Sheffield central defender Harry Souttar also copping a booking.
Piroe, the Whites' leading marksman, struck either side of half-time to move Leeds to the summit of the table on goal difference.
The win was Leeds' seventh in their last nine games overall, but just their second in their last eight away matches.
Sunderland's hopes of maintaining the pressure on the sides above them were hit by a last-gasp equaliser by Harry Leonard for Blackburn at Ewood Park.
Two swift second-half goals from Chris Rigg and Wilson Isidor had wiped out Yuki Ohashi's early opener and looked set to win it for the Black Cats until Leonard fired home in the 90th minute.
Sheffield Wednesday surged back from a 3-0 half-time deficit to snatch a point in a 3-3 draw with 10-man Middlesbrough at the Riverside Stadium.
A Finn Azaz double capped a brilliant first half display by Boro after Ben Doak's opener, but second-half strikes from Svante Ingelsson, Josh Windass and Yan Valery sealed the comeback by the hour mark while the hosts had Rav van den Berg sent off.
Derby beat managerless West Brom 2-1 as Mason Holgate's own goal proved decisive.
Jerry Yates fired the Rams in front and Holgate deflected in Kayden Jackson's effort, with Grady Diangana's goal mere consolation for an Albion team under the temporary stewardship of Chris Brunt after Carlos Corberan's departure for Valencia.
Frank Lampard got one over his old England teammate Wayne Rooney as rock-bottom Plymouth were thumped 4-0 at Coventry.
All the Sky Blues' goals came in the first half from Tatsuhiro Sakamoto, Ephron Mason-Clark and a Josh Eccles double, while Argyle had Callum Wright sent off three minutes from time.
Gary Rowett got his reign as Oxford boss off to a bright start as goals from Mark Harris, Ciaron Brown and Przemyslaw Placheta saw them cling on for a 3-2 win over Cardiff, while Rocco Vata scored deep into injury time to claim a 2-1 win for Watford against Portsmouth at Vicarage Road.
Liam Cullen's double sent Swansea on their way to a 3-0 win over QPR and first half goals from Emiliano Marcondes and Oscar Schwartau were enough for Norwich to see off Millwall at Carrow Road.
Brad Potts scored the only goal in Preston's 1-0 win over Hull and Scott Twine did likewise as Bristol City beat Luton by the same score.
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