LOS ANGELES (UPI) Houston Aeros Coach Bill Di neen looked back on a rugged series Tuesday night after his team had eliminated the Los Angeles Sharks from the World Hockey Association playoffs with a 3-2 victory. “The whole key to the series*was when Murray Hall scored in overtime in the fourth game,” he said after the Aeros completed a four games-to-two triumph in their best-of-seven Western Divi sion semifinal playoff series. Hall scored the winning goal here last Friday night to give the Aeros an overtime win annd even the series at 2-2. Houston went on to win the next three games. Hall’s score with less than three minutes left in the sec ond period Tuesday night pushed the aggressive Aeros into a 31 lead. That score proved to be the clincher when Fred Speck scored for the Sharks at 4:59 of the final period to cut the Houston margin to a single goal. The Aeros jumped off to a 2-0 lead in the first period of a pair of goals by winnger Frank Hughes, his third and fourth in the last two games. The Sharks cut the lead to 2-1 at 2:24 of the second pe riod when defenseman Ralph MacSweyn blasted in a spec tacular 65-footer for his first goal of the entire season. The Aeros now meet the Winnipeg Jets in a best-of-se ven series for the Western Di vision championship. The teams open the series in Win nipeg on Friday.