Shane Williams and Nikki Walker (thumb) found the Tigers defence difficult to penetrate
Ospreys coach Sean Holley described his side's 12-9 defeat at Welford Road as "a smash and grab raid gone missing".
Having held on by their fingernails in the first-half, the Ospreys got to within one score of victory in the second as James Hook added a penalty to Shane Williams' earlier drop goal.
Then came the defining moment of the game with the Ospreys being awarded a penalty at the foot of the home posts.
Ryan Jones ordered a scrum, but it was the Tigers who came up with the ball and cleared their lines to snuff out the match-losing threat.
"We let a real chance go begging in the end, but I'm still very proud of the players. They showed great character to hang in there right to the end," said Holley.
"It was a smash and grab raid gone missing. But we have the consolation of a losing bonus point and we are still right in this Pool and fighting.
"It is a measure of how far we have come as a team that a packed house at Welford Road, and all the Leicester Tigers players, were so happy with a 12-6 victory. We have come here in the past and been blown away in the second half, but I thought our tactical substitutions worked well for us this time and we were right in their fighting to the end.
"We need to be a bit more clinical and we need to learn from this game and improve before we meet Perpignan next weekend. But overall I'm quietly pleased."
Rob Howley and Josh Lewsey addressed more than 250 community club coaches and referees at the first WRU National Community Conference on the weekend. The volunteers benefitted from coaching masterclasses and workshops in a bid to connect all levels of the rugby pathway in Wales.
UEFA has today confirmed the Football Association of Wales (FAW) has been successful in its bid for the Millennium Stadium to host the 2017 UEFA Champions League Final on Saturday 3rd June, 2017 (kick-off: 19.45hrs GMT).
The winners of a filmmaking competition organised by the education charity Into Film and the WRU enjoyed a behind the scenes tour of the Millennium Stadium - and a chance to be photographed with the WRU's fire-breathing, rugby loving mascot, Scorch The Dragon, and Welsh international, Jake Ball.
The Wales Under 20 camp are in a quietly confident mood as they face Ireland in the U20 Championship, with Coaching Co-Ordinator Allan Lewis and full back Dafydd Howells targeting a top five finish in the tournament.
Wales U20 may start as favourites against Japan this evening in the U20 Championship, but Team Manager Mark Taylor is warning against complacency. He is also hoping a good win will boost morale and 'kickstart' performances.