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."
The WRU's Women and Girls legacy events - #TRY OUR GAME have proved popular this week with current players and newcomers to the game learning new skills and picking up tips from national squad players.
We caught up with Shona and Ellie from the Wales women team ahead of the start of the Women's Rugby World Cup in Paris next month at a recent women's training session to encourage and promote more women and girls to try their hand at rugby. #tryourgame
The Women's Rugby World Cup warm-up clash between Wales and USA proved bittersweet for centre Elen Evans. Despite being one of the star performers on the day on her 50th Test appearance, USA edged home 10-7 at Cross Keys.
Wales completed their Junior World Championship campaign with a victory over Samoa. Team manager Mark Taylor and No 8 James Benjamin reflect on a tournament which saw Wales win three games and lose two.
Wales U20 players Angus O'Brien, Nicky Thomas and coach Richard Hodges are determined to finish their Junior World Championship with a flourish when they tackle the big hitting Samoans tomorrow in Auckland.