Passage: On 1 July 2015, Bayern Munich announced they had signed Costa for a transfer fee of €30 million. Costa signed a five-year contract. The €30 million transfer fee was the fourth-highest in Bayern's history. He was given the number 11 shirt previously worn by Xherdan Shaqiri. He made his debut as a starter on 1 August in the 2015 DFL-Supercup away to VfL Wolfsburg, crossing for Arjen Robben to open the scoring in an eventual 1–1 draw; he netted his attempt in the subsequent penalty shoot-out, but his team lost nonetheless. Costa scored his first Bundesliga goal in his first Bundesliga game in a 5–0 win against Hamburger SV. On 21 May 2016, Costa scored the winning kick of the penalty shootout against Borussia Dortmund to win the 2016 DFB-Pokal Final and secure a league and cup double for Bayern.Costa enjoyed a good first season at Bayern scoring seven goals in 43 matches throughout all competitions. He started the season in great form and had 12 assists in his first 13 games. Then he picked up a muscle injury, and missed the last four games before the winter break. After the winter break, Costa could not regain his former form. In 27 Bundesliga matches, Costa scored four goals and had 14 assists.

Question: Who was Costs playing against when he scored his first goal?
Hamburger SV