West Ham boss Slaven Bilic remains a fan of Jose Mourinho despite claiming the Manchester United manager's standards have dropped.
Bilic takes his side to Old Trafford twice in the next five days, in the Premier League on Sunday and the EFL Cup quarter-finals next Wednesday, and is likely to be afforded a hot reception after his assertion that Mourinho is not achieving the success he once was.
"Jose Mourinho is one of the greatest," Bilic told the BBC.
"Statistically at home, there is probably no-one better. But it's hard to stay at that standard and maybe that has dropped now."
Mourinho once held the most envied home league record in world football with a nine-year unbeaten run across spells at Porto, Chelsea, Inter and Real Madrid.
Sporting Gijon finally broke the spell in April 2011 at the 151st attempt with a 1-0 win at Madrid's Santiago Bernabeu while his 78-match unbeaten record in English football with Chelsea fell at the hands of Sunderland in April 2014.
Crystal Palace, Southampton, Liverpool and Bournemouth all subsequently won at Stamford Bridge before the axe fell in Mourinho's second spell at the Blues.
Only Manchester City have beaten United on their own turf this season but Bilic, who is under pressure himself with West Ham just one point above the relegation zone, believes his side can cause an upset at the weekend.
"I'm confident, if we can cut out the mistakes, and with a bit of luck, we can pick up a result on Sunday," he said.