Cambridge United head coach Neil Harris believes the U’s have ‘something to build on’ after an improved performance in a 3-1 defeat at Sky Bet League One leaders Portsmouth last night. The U’s boss had demanded a reaction from his players following Saturday’s disappointing 1-0 home defeat to Cheltenham Town and saw his side test the Pompey backline in the opening stages. After a couple of half-chances they deservedly took the lead in the 38th minute when Danny Andrews’ header from Sullay Kaikai’s corner was adjudged to have crossed the line. But the leaders drew level from the penalty spot a m…