* Chelsea and Benfica ease through to last four * Basel topple Tottenham 4-1 on penalties * Fenerbahce get past Lazio behind closed doors (Adds details) By Sonia Oxley April 11 (Reuters) - European heavyweights Chelsea and Benfica reached the Europa League semi-finals on Thursday and were joined by lesser lights FC Basel and Fenerbahce who made the last four of a continental competition for the first time. ... More...