But Bath only had themselves to blame for the defeat after they amazingly chose not to take a drop goal chance in front of the posts in the dying minutes.
Meehan's men had lead 8-0 at the break and he said: "We had an opportunity to win the match, but we didn't take it.
"We've got to grow up and take the points. It's straightforward, it is about being ruthless, getting the job done and getting it through the sticks. Simple.
"Drop-goals and penalties win games. Biarritz kick the penalties and keep the scoreboard ticking over - we didn't do that."
Wasps counterpart Tony Hanks took the positives from their heartbreaking 18-16 defeat at holders Toulouse.
Fly-half Dave Walder, who had earlier scored 11 points, missed a last-gasp penalty as the champions prevailed thanks to David Skrela's six penalties.
Hanks said: "There's real disappointment in our changing room. We came here to win and didn't just come here to make up the numbers.
"We were excellent in defence for the second week in a row but Toulouse are a quality side and they just kept coming at us.
"But I'm really proud of the players. What we need to make sure of is that people aren't just talking about what we did in round one. We have to kick because we still want to qualify from this pool."