Newcastle manager Rafael Benitez fears he will have to cope without Dwight Gayle for several weeks after the striker suffered a hamstring injury in the win at Brentford.
Promotion-hunting Newcastle earned a 2-1 victory to move to the top of the Sky Bet Championship, thanks to goals from Gayle and his replacement off the bench, Daryl Murphy.
Gayle limped off in the 28th minute, after becoming the first player to score 20 goals in a season for Newcastle since Alan Shearer.
His goal was a classy strike, with Gayle racing clear down the left and cutting inside before rifling an unstoppable shot across goalkeeper Dan Bentley and into the far corner.
Benitez also lost substitute Vurnon Anita to an ankle injury in the second half following a crunching Maxime Colin tackle, with Isaac Hayden another casualty of the trip to west London.
"It was a pity we lost Dwight because he was in form, but now it looks like we will lose him for some games," Benitez said.
"I was pleased with the players coming off the bench and proud of the team because they had to work so hard and manage the situation. We knew it would be a difficult game because we watched them and they play good football.
"I am quite old so I have had this situation where you lose three players to injury before. It meant we had to defend almost with five at the back but as the game went on you cannot stop every cross and every second ball."
Benitez added: "We had to defend well but I don't think they will be very happy with some decisions like us, but in the end we got three points."