Firmino shines for Liverpool as Alexander-Arnold struggles once more.
Liverpool came back from two goals down to lead Brighton & Hove Albion at Anfield, but they couldn't hold on to the three points, drawing 3-3 in the Premier League.
Leandro Trossard scored twice in the first 20 minutes for the hosts, and it was only thanks to Alisson that Liverpool didn't fall further behind.
Jordan Henderson combined with Mohamed Salah, who cut the ball back for Roberto Firmino to score for the Reds. A VAR review was required to confirm Salah's compliance and reduce the deficit to one goal before halftime.
Luis Diaz was introduced at halftime, and Liverpool didn't take long to restore parity as a result of his left-sided play. The Colombian international attempted to isolate defenders and soon found Firmino, who beat his man inside the box before finishing clinically past Robert Sanchez.
Jurgen Klopp's team completed their comeback less than 10 minutes later, buoyed by momentum. Sanchez failed to deal with Trent Alexander-corner, Arnold's and Adam Webster had little chance as the ball deflected off him and into the back of the net.
Liverpool appeared to be in command after taking the lead, until Virgil van Dijk missed a cross from the left flank in the 83rd minute, allowing Trossard to finish at the back post.
The visitors earned a point thanks to Alexander-free Arnold's kick, which required a late touch from Sanchez.
The Reds' strong response after falling behind 2-0 helped them regain momentum, with much more intensity assisting them in creating chances to win the game. When called upon, Firmino was clinical.
Liverpool had to rely on Alisson on numerous occasions, with the Brazil international goalkeeper making a number of crucial saves. The defense appeared to lose concentration at times, and they could easily have conceded more than three goals on another day.
Manager evaluation (out of 10; 10 being the best)
7 - Jurgen Klopp It would be unfair to blame Jurgen Klopp for Liverpool's poor start, as both goals were conceded due to avoidable errors. Diaz's introduction changed the game, allowing the Reds to level the scores quickly after the restart.
Player evaluations (players introduced after 70 minutes get no rating)
GK Alisson 8 - Brighton could have been 3-0 up in the first 15 minutes but for Alisson's interventions, who did his best to keep Liverpool in the game with crucial saves.
DF Konstantinos Tsimikas (Greece) 7 - The Greece international was one of Liverpool's standout defenders, impressing on the ball while preventing danger from coming down his flank. Close to the hour mark, he was replaced by James Milner.
DF 6 Virgil van Dijk The Liverpool defender made a crucial save after a dangerous cross was fired across the box, but he must do better with the ball that got past him for Brighton's equalizer.
DF Joel Matip 7 - When possible, looked to bring the ball out from the back and was aggressive in possession. The 31-year-old also made a number of crucial clearances throughout the game.
DF Trent Alexander-Arnold (5 points) Trossard doubled Brighton's lead after the right-back made a poor decision to chest the ball down. The Liverpool star looked better in the second half, but there are some moments in the game that he will try to avoid in the future.
MF Fabinho 5 - Appeared to be slow to react in the buildup to Brighton's first goal, and could have started better. At times, the 28-year-passing old's could have been better, and he appeared labored.
MF Thiago 6 - The Spain international was bright at times, but his passing wasn't up to his usual standard in midfield. When Diaz was introduced in the second half, everything clicked.
FW Roberto Firmino 8 - Firmino's first goal required a VAR review, but his second was unassailable as he beat his man in the box before finishing on his left foot to tie the game.
Mohamed Salah, FW 7 - Salah had Liverpool's best chance of the first half, drawing a strong save from Sanchez, and it was Salah who timed his run perfectly before finding Firmino to score moments later.
Diaz, Luis (Carvalho, 46) 7 - Made an immediate impact by regularly challenging Brighton defenders down the left channel before assisting Firmino for the equalizer.
James Milner (Tsimikas 59) 6 - Did a good job stretching the play, but he could have been tighter to Trossard, who completed his hat trick in the 83rd minute.
Harvey Elliott (Henderson, 59) 6 - The England under-21 international impressed with his aggression in midfield, assisting Liverpool in maintaining their press late in the game.
Diogo Jota (Firmino, 76) N/R - Replaced Firmino in the closing stages of the game.
Darwin Nunez (Thiago, 89) N/R - Replaced Thiago as Klopp sought a game-winning goal.