Liverpool opened the gap at the top of the Premier League to an astonishing 11 points, thanks to their goalscoring hero Virgil van Dijk  But it was far from plain sailing for Jurgen Klopp’s side as Alisson was dismissed 13 minutes from time as he raced out of his goal, and handled beyond the penalty area, to deny visiting sub Leoandro Trossard   The blatant handball left referee Martin Atkinson with no option but to dismiss he Brazilian keeper, and that left the Reds clinging on grimly when Brighton skipper Lewis Dunk scored from the resulting free kick  It was a bizarre goal, with sub keeper Adrian not ready when Dunk rolled the ball slowly into the far corner under a jumping wall – but Atkinson had blown the whistle and despite home protests the goal was allowed to stand  Here are five talking points. 1. Set-pieces work again   Since the start of last season, according to Opta , Liverpool have scored 41 goals from set pieces (including penalties)  That is 10 more than any other side in the Premier League. And it’s no fluke either   In 2017-18, Bournemouth finished top of the set piece chart, Manchester City second Jurgen Klopp realised it gave footballing teams a real advantage, and introduced changes at Melwood  He brought in set piece experts including a throw in coach, and used stats and meticulous planning to improve output And it’s worked – those goals have won tight games and have underpinned Liverpool’s title challenges over the two seasons  It helps of course, when you have the delivery of Trent Alexander-Arnold to rely on, as Virgil van Dijk will testify 2. Van Dijk leads the way  Van Dijk is something of a set piece expert himself. Since the start of last season, no Premier League defender has scored more goals, and again it’s no co-incidence Klopp set him a target of improving his goals output, given the massive advantage has physically  After scoring on his Liverpool debut in 2018, he didn’t find the net again that season But improvement has come, and now he has 10 Liverpool goals. Klopp will demand more though, because they are crucial against sides who park the bus like Brighton did here – and did well  They stopped the Reds from creating little in open play, so it’s important to carry a threat from set pieces in games like that Two goals here, one against Napoli and a winner at Palace in their last three games underline just how important 3. Brighton play their part  Brighton actually better some decent football in the first half, especially when they went behind, and it’s easy to see why Graham Potter carries the confidence of his club, and wass awarded a new contract so quickly – with so many managers under pressure in the Premier League, an English one who plays attractive football under pressure is an attractive proposition  But the set piece weakness displayed at Anfield did undermine their ability to frustrate Liverpool and actually put the home side under pressure If they’re not careful, it could pitch them worryingly close to the relegation zone 4. Salah out of sorts  Mo Salah is struggling for his usual form at the minute after six weeks of managing an ankle injury, but reducing his training time  He has hardly trained during the week over that period, just on the Friday before a weekend game, and that seems to have affected his rhythm and fluency So it was no surprise when manager Jurgen Klopp replaced him after 69 minutes.  Well, no surprise to everyone but Salah himself – who threw what appeared to be an almighty strop when Adam Lallana came on in his place  He shook his head, looked stunned, and then refused to look at the manager as Klopp tried to hug him It shows though, his desire to stay on and score goals – a proper striker. 5. Justice for the 96  Before the game, there was a touching moment as the Kop showed their support for the Hillsborough families – and their belief that justice must still be done over that terrible, preventable tragedy  They sang ‘Justice for the 96’ for the first six minutes of the game, and then broke into passionate support of their team It is a reminder of just how difficult in the corrupt British systems of how difficult it is to get real justice  Even when it was proved 96 fans were unlawfully killed and Liverpool fans were NOT to blame, it seems no one else will ever be brought to justice  They will not forget though, and will not give up – and that was perhaps the most important message to take from an afternoon where Liverpool’s title chances grew stronger