During his regular post-match Review Show, which is now available to watch on LFCTV GO, the former Red analysed just how Arne Slot's side produced such a dominant performance in north London on Sunday.
Szoboszlai was on the scoresheet and recorded an assist in the win, while Salah delivered two of each to leave Liverpool four points clear at top of the Premier League at Christmas.
"It felt like a statement victory," Mellor said. "It was just an absolute joy to watch, it really was, and it could have been a lot more than six. Szoboszlai was just sensational – he was everywhere!
"His work-rate was superb – he was back at right-back at one point to win the ball from Son [Heung-min].
"It was just an all-round top performance. He scored and was directly involved in four of the other five goals."
Mellor also hailed Salah's contribution as the No.11 made Premier League history by hitting double figures for goals and assists before Christmas, becoming the first player to achieve the feat.
"I think he's easily the greatest modern-day striker that we've had," Mellor declared.
"He scored two, he could easily have got the hat-trick and even more. There is no-one better in the Premier League."