David Luiz has labelled Manchester United duo Nemanja Matic and Romelu Lukaku as "fantastic" players and hopes the former Chelsea boys don't come back to haunt them on their Stamford Bridge return.
Chelsea made the surprising decision to sell Matic to their Premier League rivals for £40million this summer, while Jose Mourinho also pipped the Blues to Lukaku's signature.
Matic was named as man of the match in midweek when United faced another of his old sides, Benfica, in the Champions League on Tuesday, which led to Chelsea coach Antonio Conte being asked once again why the Blues decided to sell the midfielder to a direct title rival.
While Conte dodged the question posed to him in his pre-match press conference ahead of Sunday's clash with United, Luiz admitted that Matic's "great" quality is why he has done so well with the Red Devils this season.
Speaking exclusively to Standard Sport, the Brazilian defender said: "Everyone can also say how well he did at Chelsea.
"He's a fantastic player. I've known him a long time since Benfica. He's a great player so it's normal for me [that he's done so well at United]."
Another former Chelsea player who Luiz will come up against at Stamford Bridge on Sunday is Lukaku.
The striker enjoyed a strong start to the campaign after completing a £75m move to United from Everton in July, but has since failed to score in his last six games.
In Pictures | Roma vs Chelsea | 31/10/2017
Luiz will be tasked with the aim of trying to stop Lukaku from breaking that drought at Stamford Bridge this weekend, and the Chelsea defender said: "Lukaku is a fantastic player, and a great friend.
"[But] I hope he cannot score against us."
Chelsea had appeared to put a bad run of results - losses to Manchester City and Crystal Palace in the league and a 3-3 Champions League draw at home to Roma - behind them when they beat Bournemouth last weekend to record their third straight win in all competitions.
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But a 3-0 humbling defeat at the hands of Roma at the Stadio Olimpico on Tuesday resulted in yet more criticism for Conte's men ahead of their Premier League clash against United this weekend.
With the champions already trailing Premier League leaders Manchester City by nine points, Thibaut Courtois told Standard Sport that the match with United is now a "must-win".
And Luiz has echoed Courtois' sentiments, insisting the clash on Sunday will be a "massive" one for Chelsea.
"Of course, when you lose one game the next one is massive so I think the same way," he added.
"It's always important to understand the philosophy when you attack or defend, doesn't matter about midfielders. The strikers are the first defenders. And the first defender is the first striker to build from the back.
"Sometimes things are going well, sometimes not. This is football so you need to be clever to understand the moment and win games."
Luiz was speaking to Standard Sport at the launch of Hublot's new Chelsea Big Bang watch, the second timepiece the Swiss watchmaker has created in partnership with the Blues.