Foster, 26, is set to face Besiktas in Istanbul tonight as United begin their Champions League Group B campaign.
The England goalkeeper has been an ever-present for United so far this season with regular No 1 Van der Sar sidelined with a thumb injury.
Van der Sar is likely to be out for at least another month, thereby handing Foster the opportunity to cement his place in Sir Alex Ferguson's starting line-up.
And the former Stoke and Watford goalkeeper admits that he is now relishing the benefits of playing regularly for United.
He said: "I've really enjoyed being involved so far. It's what I have wanted.
"When you have a solid run in the team, you can look forward to games in advance and settle down a bit more.
"I'm happy with what I've done so far and hopefully there's more to come.
"Obviously the World Cup is in sight at the end of the season and it's therefore important that I do well in any games I play.
"I've started the season reasonably well and played every game so far, and long may it continue."
United's clash with Besiktas in the Inonu Stadium on the banks of the Bosphorus is their first European clash since the disappointment of losing the Champions League final against Barcelona in Rome last season.
The Premier League champions relinquished their grip on the European Cup against Pep Guardiola's team and United defender Patrice Evra admits the pain of the defeat still hurts.
Evra said: "I'm a winner, I like to win, so I still think about what happened in Rome.
"Everybody says we did well last season and we won three trophies, but when you lose the final in the manner we did, where we didn't give a true account of ourselves, it's very frustrating.
"We didn't show people the real Manchester United and we were very upset with ourselves.
"We missed a big opportunity in Rome and that's a real shame. It killed all my dreams last year.
"When I think about last season now I don't think about winning the league or the Club World Cup or the Carling Cup.
"All I think about is losing in Rome and that's made me very determined to do well this year and make up for that."