Gelsenkirchen, March 31: Schalke 04 on Saturday stretched its winning streak to six games after beating Freiburg 2-0 in the Bundesliga 28th round, tightening its grip on the second position in the German league table. Both teams failed to score in the first half, but Daniel Caligiuri opened the scoring for Schalke after converting a pelty in the 63rd minute, reports Efe.