"I'm relieved because we gave them opportunities to get back in the match," said Richards.
"But we created a lot of chances against a Wasps side which is renowned for its defence and had two or three other chances to score."
Richards, Harlequins director of rugby, added: "We played reasonably well but I don't think anyone was outstanding on the day.
"We didn't finish Wasps off when we had the opportunities and the last 10 minutes were a bit of a dogfight."
His Wasps counterpart, Ian McGeechan, concurred: "After 30 minutes I'm wondering how the hell we are still in the game and in the last 30 I thought it was there for the taking for us but we didn't finish.
"Quins started very well and looked sharp and we did well to get some points on the board.
"I felt in the second half we'd got the measure of them and should have been a little bit more ruthless how we finished off."
The match may have been tense from a coaching perspective but it was a thriller for more than 10,000 fans.
Richards said: "One-point win, end to end stuff and plenty to shout about." And Wasps coach Shaun Edwards agreed, adding: "It was a great advertisement for the GUINNESS PREMIERSHIP."
