Soccer-Chelsea stretch lead at top of table with win over Hull

* Chelsea extend Premier League lead to eight points * Costa, recalled to team, scores shortly before halftime * Cahill ensures victory with headed goal in 82nd minute * Game halted for nearly 10 minutes after Cahill and Mason clash heads * Mason leaves field on a stretcher, holding oxygen mask * Chelsea visit Liverpool next, Hull travel to Manchester United CHELSEA 2 HULL CITY 0 LONDON, Jan 22 (Reuters) - Chelsea extended their lead at the top of the English Premier League to eight points on Sunday when recalled striker Diego Costa set them on their way to a 2-0 home win over struggling Hull City. Costa scored shortly before halftime after wing back Victor Moses ran at the Hull defence and found the Spain striker in a crowded penalty area with his cross. Costa missed last weekend's win at Leicester City with what Chelsea officials said was a back strain. British media reported that a row with backroom staff and a possible lucrative transfer to China were the real reasons behind his absence. Chelsea captain Gary Cahill made sure of the victory when he headed home unchallenged from a Cesc Fabregas free kick in the 82nd minute. The win against Hull allowed Chelsea to capitalise on the failure of their closest title rivals to win at the weekend, except for Arsenal who beat Burnley 2-1 earlier on Sunday. Hull remain one place above bottom-placed Sunderland. Hull midfielder Ryan Mason was taken to hospital after a clash of heads with Cahill in the first half which halted play for almost 10 minutes. Mason left the field on a stretcher holding an oxygen mask and was taken to hospital for checks. (Reporting by William Schomberg; Editing by Clare Fallon)