Chelsea boss Frank Lampard has defended Antonio Rudiger after he was criticised for his part in Tottenham forward Son Heung-min's red card on Sunday.Spurs manager Jose Mourinho was unhappy with the Blues defender's reaction to Son's challenge in Chelsea's 2-0 win.Lampard said it was "disappointing" to question Rudiger's integrity while an investigation into alleged racial abuse directed at the German is ongoing."I do defend Toni firmly on it," said Lampard.Tottenham's appeal against Son's red card - which was issued after VAR ruled he had kicked out at Rudiger - failed on Tuesday.The South Korea international will miss a home fixture against Brighton on Boxing Day, as well as trips to Norwich on 28 December and Southampton on 1 January.Mourinho thinks it should be Rudiger's reaction to Son's challenge that is coming under scrutiny, and not Son's action."I'm not speaking about the racism incident, this is another thing. I am speaking about that incident, the red card," he said on Monday."In the Premier League I love there is no space also for what Rudiger did. Stand up and play man. This is the Premier League."Lampard responded: "With Toni, in this incident when he's having to post after the game about something we know is a huge deal [racism], I think to question his integrity in that time is disappointing for sure."Pretty universally, certainly what I heard in the commentary and the post-match reflection was that the Son incident was a red card."It wasn't brutal but it was instinctive that warrants a red card in the modern day. It was pretty clear that was the case. I wouldn't question Toni's integrity on that."On Tuesday, Tottenham said they had banned a supporter for throwing a cup at Chelsea goalkeeper Kepa Arrizabalaga, but their investigation into the alleged racist abuse of Rudiger "remains ongoing".

'I support all my players in this situation'

Both Rudiger and Son were subject to alleged racist abuse during the fixture.Rudiger said he heard monkey noises from the crowd, while police arrested a Chelsea fan for a racially aggravated public order offence against Spurs' Son.Lampard says he has only spoken briefly to Rudiger, who informed Chelsea captain Cesar Azpilicueta of what he had heard and he told referee Anthony Taylor.However, Tottenham say their initial findings after the alleged racist abuse of Rudiger are "inconclusive"."I saw Toni's social media post, I thought it was well put, from the heart and something that he feels very strongly about," said Lampard."I'll speak to him today when I see him. I would like to think the players know I am with them on anything like this."I'll have the same conversation with Toni that I had with Tammy after the incident earlier this year."And I will tell them and take the time to make sure he knows I support him, and that I support all my players in this situation."