A late Paul Sampson try gave London Welsh a winning start to their professional era.
Playing their first full game as a full-time club, Welsh travelled to Birmingham to take on Moseley in their National League One opener.
Sunia Koto Vuli's try, Aled Thomas' conversion and Ed Lewis-Pratt's penalty had put Welsh in the driving seat going into the closing stages.
But when Moseley took a one-point lead through a penalty with time running out, defeat was on the cards, until former England wing Sampson crossed moments later.
Meanwhile, Welsh's Academy lost out by just one point in the last minute to a touring Belgium U19 international side on Sunday.
Fly-half Sam Katz set up Joe Mathams for Welsh's opening try before converting, but the Belgians were 10-7 up at the break.
And despite a brace of second-half tries from Robbie Martey, plus two conversions and a penalty from Katz, the tourists won 25-24 thanks to the last-gasp try.