Substitute Jamie Gittens scored twice to lead Borussia Dortmund to a 2-0 win in their Bundesliga opener against Eintracht Frankfurt as former player Nuri Sahin made his debut as coach in the league. In a tight game, Gittens broke the deadlock in the 72nd minute, whipping the ball into the top corner to score a beautiful goal, and put the game to bed in the third minute of stoppage time. Former Dortmund midfielder Sahin returned to the club in January as assistant coach and has now taken over from Edin Terzic. Dortmund fans used the match to protest against the controversial sponsorship deal wi…