The club will make another bid, believed to be in the region of £40million, for the United striker this week.
Chelsea had considered Robert Lewandowski as an alternative but he has agreed a wage hike to stay at
Borussia Dortmund for another year before joining Bayern Munich next summer.
Chelsea will hold talks with Samuel Eto’o’s representatives on Tuesday as they consider a short-term offer.
Unsettled: Wayne Rooney watched the first half of United's match against Swansea from the bench
All smiles: Abramovich looked happy with the way in which Chelsea kicked off their campaign
Mourinho later underlined his determination to land Rooney — adding a sideswipe in Arsenal’s direction over their attempts to sign Liverpool’s Luis Suarez.
‘We will try till the last day to add a new player to the squad,’ he said. ‘A striker. I don’t think it’s ethical I name players who belong to other clubs. If we have to make a bid, we make it in an official way.
Banner: Mourinho was welcomed back with open arms by the Chelsea supporters
Owner Roman Abramovich had given a pre-match pep talk.
Youth: Eden Hazard was excellent for the Blues, but Mourinho said he needs older heads around him
Hull boss Steve Bruce said: ‘What a difference to 12 months ago. The whole ground is behind him, the Special One has come back.’
Pick that one out: Frank Lampard netted a free-kick after missing a penalty for the Blues
Comfortable: Oscar set Chelsea going in the 13th minute and there was no way back for Hull from there
New man: Kevin De Bruyne impressed while playing behind the lone striker