Yachvili pulled the strings as Biarritz bulldozed the Cherry and Whites up front and then ran riot out wide in arguably their most-complete performance of the season.
The fact that it came on the back of a mumps scare and a raft of injury problems that disrupted their preparations was even more pleasing for the France scrum-half who now wants more of the same at the RDS on April 27.
"It was a very good game for us and we are very proud of the team," said Yachvili, who made 18 appearances for Gloucester during a single season spell in the West Country in 2001/02.
"It was a good return for me personally. I was very proud to be back at Kingsholm. Since I left in 2002, I haven't been back because I was injured for the Heineken Cup game in 2010.
"I was a little bit scared because Gloucester have been playing well in the Premiership and the Amlin Challenge Cup since the beginning of the season.
"And it wasn't an easy week for us because training was very difficult due to the amount of injuries in the squad. We had a lot of absentees but the young players who came in played very well.
"We knew at half-time that that the 27-14 scoreline would not be enough because, with the wind against us, the second half would be harder. The wind helped them to get into our half but we defended well and scored important turnover tries.
"We've had a very hard season but it's not over yet because we are now in the semi-final of the Amlin Challenge Cup and we have a title to defend.
"We are playing without pressure. We are just playing our rugby."