An already injury-hit Leeds were forced to make two more changes without talisman centre-back Pontus Jansson and goalkeeper Bailey Peacock-Farrell, who are recovering from foot and knee injuries respectively.
Peacock-Farrell’s setback left Leeds without a recognised first-team goalkeeper last week, with former loanee Jamal Blackman having broken his leg and returning to parent club Chelsea.
With United not signing an emergency loan goalkeeper, 20-year-old Academy graduate Will Huffer was handed a debut between the sticks by head coach Marcelo Bielsa with fellow 20-year-old Finn Aapo Halme also filling in for Jansson at centre-back.
Bar the odd set piece, the duo were rarely threatened by a fairly toothless Robins side, who shot themselves in the foot when Josh Brownhill was sent off for a second booking in the 55th minute.
The dismissal proved the catalyst for a Whites onslaught with Lee Johnson’s visitors fortunate to only concede twice to strikes from Kemar Roofe and Pablo Hernandez.
At the other end of the pitch, Halme and Huffer helped United to their seventh clean sheet of the season – impressing Phillips who himself is a graduate of the club’s Academy.
“I thought they did exceptionally well, both of them,” said Phillips.
“I’ve been there and it is nerve-wracking but they handled it very well and it is a credit to Leeds United and the academy.”
Midfielder-turned-defender Phillips lined up in a back three alongside Halme and captain Liam Cooper and the trio plus goalkeeper Huffer survived a few nervy moments in the first half.
Two headers from Lloyd Kelly both threatened while Huffer was fortunate when punching clear a cross directly to Jamie Paterson, who could only send his lob over the bar.
Leeds had two clear chances in the first half with visiting goalkeeper Niki Maenpaa tipping a rising Gjanni Alioski volley over before a deflected effort from Roofe trickled past the post. But the Robins were left stuffed shortly before the hour mark when the already-booked Brownhill lunged at Roofe in the centre circle and was sent for an early bath. United then created a plethora of chances – especially after the introduction of substitute Samu Saiz – with Alioski, Roofe and Jack Harrison squandering opportunities before Maenpaa brilliantly prevented a Barry Douglas effort which seemed destined to find the top right-hand corner.
A United opener looked inevitable and City finally crumbled in the 69th minute when Roofe diverted home a shot from Hernandez from close range.
Leeds then ensured victory with Hernandez making sure there was to be no City comeback when, four minutes from time, he neatly looped a header over Maenpaa following a superb reverse pass from Saiz.
The victory was a welcome way for United to bounce back from the 4-1 hiding at West Bromwich Albion before the international break. and keeps them third in the table, one point behind second-placed Middlesbrough and three behind leaders Norwich City
United’s players dedicated the victory to Blackman with Cooper holding aloft Blackman’s shirt in celebration of Roofe’s goal.
Phillips said: “With the sending off, I am a modern-day midfielder and I think it was a bit harsh to be honest.
“We have had yellow cards for the same thing but I think it was a turning point.
“But as a Leeds United player I thought that we were well on top.
“I thought they maybe had some threat from set pieces but other than that they didn’t really catch us out on anything.”
“Obviously it was very disappointing for us at West Brom, and then having two weeks to dwell on it. It’s not good but we came in last week and worked really hard. The manager told us what we’d done wrong and this shows that we’re improving as a team.”
Leeds United: Huffer, Halme (Saiz 64), Phillips, Cooper, Dallas, Forshaw, Douglas, Klich (Baker 82), Hernandez, Roofe, Alioski (Harrison 61). Unused substitutes: Miazek, Davis, Clarke, Shackleton.
Bristol City: Maenpaa, Webster, Brownhill, Weimann, Adelakun (Walsh 62), Kelly, Eliasson (Diedhiou 62), Paterson (Eisa 78), Pack, Kalas, Hunt. Unused substitutes: O’Leary, Pisano, DaSilva, Baker.
Referee: Scott Duncan (Northumberland).