Marcelo Bielsa was left frustrated by Leeds' finishing after they clung on against Swansea despite dominating the Sky Bet Championship clash.
First-half goals from Pontus Jansson and Jack Harrison set Bielsa's side up for a commanding victory but Leeds spurned a host of chances and had to repel a late Swans charge after Oli McBurnie's 87th-minute penalty.
United held on to record a 2-1 win that moved them back to the top of the table following Norwich's defeat at Preston and ensured they go into a 10-day break in high spirits.
"I think we deserved to win," said Bielsa. "It's hard to understand why we only won by one goal because we dominated the game and had many chances to score.
"When we win the game we can wait for the next game with serenity."
Leeds went into Wednesday's match on the back of a late draw at Middlesbrough, a contest that was overshadowed by Jack Clarke collapsing in the away dugout in the closing stages.
The 18-year-old is continuing his recovery after being released from hospital late on Saturday evening and Bielsa told his winger that the victory over Swansea was for him.
"We would like to dedicate this win to Jack Clarke because each of us feels he deserves this win," said the Leeds head coach.
"We hope he will recover well and will let him take all the time he needs to recover."
The game had an edge after Swansea pulled the plug on Daniel James' move to Leeds in the final stages of deadline day and the youngster produced a lively display on his first return to Elland Road since leaving in disappointment a fortnight ago.
James was substituted midway through the second half to a good reception from both sets of fans.
Swans boss Graham Potter was proud of the 21-year-old's character after a difficult couple of weeks.
"It was a tough evening for him but he gave his best," he said. "It wasn't an easy night for anybody.
"He had some dangerous moments and you could see what he's about. He'll get better and learn from the experience."
Despite suffering only a second defeat in eight games, Potter was encouraged by his side's performance.
"Leeds have got as good a chance of getting promoted as anybody from what I've seen," he added.
"That's as tough a test as we've had this season. Leeds are a good team and played well.
"You saw the character of our players not to go under because you can quite easily go under here. They didn't and stayed in the game. That's a learning point for them as they go forward.
"You can't just dominate games and play nice football at these places. You've got to survive and dig in. We did that to enable us to at least make a fight of it in the end."
