Leeds are 80/1 for the Carabao Cup but their win over Port Vale was overshadowed when Samu Saiz was accused of spitting.
Saiz, a reported £3million summer signing from Spanish club Huesca in July, took 13 minutes to make an impression when he smashed home a rebound from close range.
Despite Michael Tonge's equaliser against his former club, Saiz netted twice more in as many minutes in the second half, before fellow debutant Caleb Ekuban added a late fourth.
The victory means Leeds can be backed at 80/1 with Sky Bet to go on and lift the trophy this season.
However, Vale boss Michael Brown was incensed and alleged the hat-trick hero had spat in the face of one of his players shortly before half-time.
"I think the boys lost focus a little bit," said Brown, who spent three seasons at Elland Road before departing in 2014.
"The guy who scored three goals spits in Joe Davis' face in the 40th minute and it is very hard to take. So that certainly knocked us off balance. We asked their staff to take him off, they ignored that and he scored three goals.
"That is why it was getting a bit heated down in the technical area."
Ched Evans came off the bench to rescue Sheffield United, who came from behind to beat League One Walsall 3-2 at Bramall Lane.
Amadou Bakayoko gave Walsall a half-time lead but Evans' introduction changed the course of the game, with his 74th-minute shot deflecting in off Kory Roberts.
Evans turned provider again to set up Nathan Thomas for the Blades' second, before Caolan Lavery made the game safe.
Erhun Oztumer reduced the deficit for Walsall with an injury-time penalty but it was too late to salvage extra-time.
Aston Villa also progressed after a tight 2-1 win at Colchester, Scott Hogan scoring the visitors' opener before Mikael Mandron missed a penalty for the home side.
Frankie Kent put through his own goal to inadvertently extend Villa's lead before making amends when he netted at the right end to make it 2-1 shortly before half-time.
Villa head into the next round as 66/1 chances at Sky Bet.
Lucas Akins scored a late penalty as Burton came from behind to edge past Oldham 3-2 at Boundary Park.
Luke Varney's opener early in the second half was cancelled out by Paul Green's free-kick for the hosts, who then grabbed the lead through a Craig Davies spot-kick.
Matty Lund equalised within two minutes and Akins grabbed the winner after Ryan McLaughlin conceded a foul in the box.
Bolton also came from behind to win 2-1 at Crewe, late goals from Adam Armstrong and Derik Osede cancelling out Chris Porter's headed opener for the hosts.
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