Ronald Koeman was unimpressed by Jose Mourinho's pre-match comments about Everton's expenditure and expectations, so too Manchester United's performance despite their comprehensive win on Sunday.Antonio Valencia got the hosts off to a breathtaking start as United's all-time top scorer Wayne Rooney made his first return to Old Trafford - the day before appearing at Stockport Magistrates' Court on a drink driving charge.The 31-year-old spearheaded Everton's hopes of a point before tiring and being taken off late on - a change followed by a dramatic collapse as Henrikh Mkhitaryan, Romelu Lukaku and Anthony Martial secured a 4-0 win for the hosts.The scoreline may have been harsh but Koeman's men have now not won in six matches in all competitions, losing their last four without scoring and conceding 12 goals in the process."I felt, really, on the touchline, there is something possible this afternoon because I wasn't so impressed by United," the Everton boss said."That is maybe strange after a 4-0 defeat but, yes, they were really clinical and we didn't deserve this high defeat. Okay, that's football."Koeman felt his side were better than Thursday's abject 3-0 Europa League loss at Atalanta and made life difficult for United, with summer signings Rooney and Gylfi Sigurdsson having their best chances.Mourinho pointed at such high-profile acquisitions in his programme notes, saying Everton had spent over Â£140million during the summer and want "at least to secure a top four position this season"."Every manager in life has doubts," under-pressure Koeman said. "There is no-one who has no doubts in life, in football as a manager."And if you don't win and you have a big number of players in your squad and you have doubts about how you need to start, the system to play, but that's normal."Of course, I ask myself the question, 'why, why?'"But, okay, if Mkhitaryan of United gets one year to adapt to the Premier League, we have eight new players. Maybe I give them also one year, one season to adapt to the Premier League."That was nice because I read the programme of United and my colleague [Mourinho] told about Everton 'they spending Â£140million', 'they need to go for the top four'."Sorry, if there's anybody in this room and outside who sees something realistic (about) what is possible for this Everton, please come on. Be realistic and let's talk at the end of the season."I am not happy (with) how we start the season, but please (be) a little bit realistic about Everton and that starts with everybody, fans, press."We need time, but it's difficult in football."Koeman believes "the same as last season" is realistic for Everton, who finished seventh in the Premier League in the Dutchman's first campaign.United ended sixth last term but now look like genuine title contenders under Mourinho.Manchester City are another side that have started the league strongly and secured a 6-0 win at Watford this weekend, but the United boss did not give them a second thought.Mourinho did, though, have the fact Arsenal, Chelsea, Liverpool and Tottenham dropped points in his mind."Today I didn't think one single second in Manchester City," the United boss said."I thought about Tottenham, Arsenal, Chelsea, Liverpool, they lost, well, they didn't win their match and it was a chance for us to get two points, like they got last week when we drew against Stoke so I just thought about them, not City."City won the game and did their job, I was thinking about the others, and when I saw their results, I thought it was an opportunity we cannot waste."