Kagawa's 12th goal of this season beat the previous Japanese record set by Naohiro Takahara, but he still expressed disappointment at the wild 4-4 draw against Stuttgart
The 23-year-old scored just after the half-hour mark, at the same time setting a new record for Japanese players in major European top flights with his 12th goal of the season. The previous record-holder was Naohiro Takahara, who recorded 11 goals with Frankfurt in the 2006-2007 Bundesliga season.
"The play shaped up well, and it was a great goal that we scored as a team," Kagawa said after the match. "I'm grateful for my team-mates' help."
But Dortmund fell apart in the latter stages of the match, surrendering four goals to the visitors and exchanging the lead several times.
"It's disappointing that we drew," Kagawa continued. "Physically and emotionally it was a tough match, but if we keep playing hard in the remaining matches we'll have accomplished something."
The Samurai Blue star also praised opposing defender Gotoku Sakai, who made his eighth straight full appearance for Stuttgart.
"He was always keeping track of the run of play and looked confident," Kagawa said of 21-year-old defender.
Japan international Shinji Okazaki, still recovering from injury, was left off the bench.