Liverpool: Jordan Henderson has described the Liverpool forward line of Philippe Coutinho, Roberto Firmino and Sadio Mane as world-class and insisted their work rate is responsible for the team’s rise.

Liverpool took top spot in the Premier League for the first time since May 2014 with a 6-1 destruction of Watford on Sunday when their front three again impressed and scored. Mane scored twice to take his total for the season to six league goals.

Firmino made it five goals and three assists in his past seven Premier League appearances and Coutinho three goals and five assists in the same period. Henderson highlighted the trio’s tirelessness as key to Liverpool’s rapid development under Jurgen Klopp.

The Liverpool captain said: “They are world-class players. Their understanding of the game, not only going forward, but also the work rate they all give for the team in terms of pressing and winning the ball back high up the pitch. They all help the team defensively. The three of them are fantastic at that and going forward they are unstoppable when they are on it.

“I see them every day and, for me, they are world-class players. It’s a pleasure to be playing with them. It’s our job to ensure we offer protection for them when they are going forward and expressing themselves. As a team I feel as though we have a lot of quality and in the final third they’ve been brilliant over the past few weeks. It was very good from them against Watford but then I thought we were very good throughout the whole team.”

Henderson was part of the last Liverpool team to reach the Premier League summit when Daniel Sturridge, Raheem Sterling and Luis Suarez formed a formidable attack for Brendan Rodgers’ side but is reluctant to draw comparisons with Klopp’s potential challengers.

“They are all fantastic players, every single one of them is top class,” he said. “I don’t really like comparing this team to a couple of seasons ago. I prefer to concentrate on this team and what we’re good at and what we’re doing. That’s the most important thing. The team of 2013-14 is in the past.”

Liverpool are close to finalising contract extensions with midfielder Kevin Stewart plus two of their brightest academy prospects, Trent Alexander-Arnold and Ben Woodburn.

Stewart, 23, is part of Klopp’s first team squad at Melwood and has been offered a new five-year contract. Alexander-Arnold, who made his full debut in the recent EFL Cup win over Tottenham Hotspur, is also expected to commit himself to Anfield until 2021 while the promising Welsh midfielder Woodburn has been offered a three-year contract, the maximum extension available to a 17-year-old.

The club’s sporting director, Michael Edwards, has led the contract negotiations, in keeping with his new role, with Klopp keen to secure the trio’s services long-term. The manager’s willingness to utilise academy prospects continued on Sunday when Ovie Ejaria made his Premier League debut as a late substitute. Ejaria is already under contract at Liverpool until 2020 having signed a new deal at the end of last season.