“Six wins out of six, you can't ask for much better than that. It's not easy to do or there would be more teams doing it,” Liverpool defender Andy Robertson said.
“We've played a lot better than tonight, we weren't at our highest level, but at this point it's about winning the games and securing qualification.”
A Donny van de Beek foul on Diaz gave Salah his chance from the spot. The Egyptian missed a penalty in Liverpool's last Champions League game against Real Madrid, but made no mistake this time sending the keeper the wrong way and the ball into the bottom corner.
Aston Villa substitutes Jhon Duran and Ross Barkley bagged second-half goals to salvage a 3-2 victory over RB Leipzig in a match marked by a stunning error from keeper Emi Martinez that gifted Leipzig a goal.
With 13 points after six games, Unai Emery's men are just a win away from booking their berth in the Champions League last 16.