Frank Lampard’s young Chelsea side face a major test of their progress when they face Liverpool at Stamford Bridge in the Premier League on Sunday.Last week’s impressive 5-2 win at Wolverhampton Wanderers showed Chelsea’s potential with striker Tammy Abraham grabbing a hat-trick and two other academy products in Mason Mount and Fikayo Tomori also on target.But it has been a mixed start to the season for Lampard’s side and they have been particularly patchy at home – giving up a two-goal lead to draw 2-2 with promoted Sheffield United and losing 1-0 in the Champions League to Spanish club Valencia.Liverpool also tasted defeat in Europe with a 2-0 loss to Napoli in Italy but Juergen Klopp’s men lead the Premier League with five wins from five.The match is Chelsea’s biggest test since their opening day 4-0 loss at Manchester United and Abraham believes they will be fired up.“Sunday is a test of character. We can take our anger out against Liverpool after the European disappointment,” he said.“It’s a massive game and both teams will be going to win. We’ll look forward to putting (the Valencia loss) right,” Abraham added.“We are going to have a lot of ups and downs in a season. We’ve got to move on and not dwell on it.”Liverpool defender Virgil van Dijk, who made a rare error for Napoli’s second goal, brushed off the notion that the loss was a wake-up call for the European champions.“It shouldn’t be a wake-up call – we have been performing outstanding since the start of the season and so there is no reason to panic,” he said.Liverpool were held to a draw at Stamford Bridge last season, needing a late equaliser from Daniel Sturridge to take a point. The previous season Chelsea won 1-0 with a goal from Olivier Giroud.Champions Manchester City, beaten at promoted Norwich City last weekend will expect to get back to winning ways when they host Watford at the Etihad on Saturday.Pep Guardiola is without his two first-choice central defenders after John Stones joined Aymeric Laporte on the injury list.Brazilian Fernandinho partnered Nicolas Otamendi in the 3-0 Champions League win at Shakhtar Donetsk in Ukraine on Wednesday but 18-year-old Spanish defender Eric Garcia could be in contention for a start against the Hornets.Fourth-placed Manchester United travel to West Ham United on Sunday while Tottenham Hotspur, who are third, face a tricky trip to Leicester City.