Southampton manager Ronald Koeman explained Sadio Mane's "struggling" recent performances led to the forward being dropped for the club's 1-0 win at Swansea City on Saturday.
Shane Long's second-half header sealed a fifth win in six matches for Southampton, lifting them to sixth place in the Premier League table, a point behind Manchester United.
Mane, who has not scored in the Premier League since October, was an unused substitute and Koeman revealed a tactical change was partly the reason for the Senegal international's omission.
"We play a little bit different at the moment," Koeman said.
"We don't play with three in front, we play with two strikers, and that's one reason why he did not start.
"In the last few weeks he was a little bit struggling in his performances.
"He was working hard but, really, what he can show and what he can do for the team was not like that."
Koeman said January signing Charlie Austin can expect more chances to impress soon despite the striker again starting on the bench.
"It's all about opportunities," the Dutchman added.
"At the moment he is not starting but that can change in one or two weeks.
"It's all about what we decide to put out our strongest line-up for every game."