Jose Mourinho has vowed to silence the critics when Manchester United face champions Leicester, while his old rival Arsene Wenger hopes to celebrate a memorable milestone with a rare success against Chelsea on Saturday.Mourinho finds himself under fire less than two months into his United reign after three successive defeats and an unconvincing League Cup win at third tier Northampton.United are already trailing six points behind Premier League leaders Manchester City and another setback at Old Trafford this weekend would be a huge blow to Mourinho's bid to stamp his authority on an team that has underachieved in recent years.After winning their first three league matches under Mourinho, as well as beating Leicester in the Community Shield, United lost to City and Watford, either side of a Europa League defeat at Feyenoord.That Mourinho is at a low ebb on the same weekend that Wenger celebrates his 20th anniversary as Arsenal manager won't have been lost on the Frenchman. Wenger, who has endured many barbs from Mourinho in the past, faces Chelsea looking to improve on a woeful record of five wins in his last 31 meetings against the Blues. His last major milestone - his 1,000th match as Arsenal manager - was spoilt by a 6-0 thrashing at Stamford Bridge.But having seen a second-string team win 4-0 at Nottingham Forest in the League Cup in midweek, following a 4-1 success at Hull last weekend, Wenger is confident the depth of his squad will help restore order after a sluggish start to the season."We have four days to prepare for the (Chelsea) game, let's focus on that now," Wenger said."The performance shows that the players who played at Hull need to be on their toes and that's what we want -- competition for places."