The merry-go-round at the top of the Guinness Premiership was spinning wildly yesterday. The top two changed places and Sale Sharks sprang back into contention for a play-off position at the expense of London Wasps, although Lawrence Dallaglio made a promise that Wasps, in his final season, would be there when the music stops.

The last weekend of regular fixtures could not be more finely poised. Premier Rugby Ltd's fixture-maker must be hugging himself that next Saturday will bring a face-off between the clubs now standing first and second in the table: Gloucester, who have occupied top spot nearly all season, play at their Kingsholm fortress against Bath who are arguably finishing the season with the most effective rugby of anyone.

But not only is the play-off situation still to be decided - only Gloucester are guaranteed a top-four finish as things stand - there is a European context to be considered, too. Leicester's defeat yesterday by a Newcastle Falcons side having to cope with the imminent departure of two England backs, Mathew Tait (to Sale) and Toby Flood, understood to be headed to the East Midlands club, could cost them, for the first time in their history, a place in the Heineken Cup because they are only four points clear of London Irish.

This, of course, assumes that the top six clubs in the Premiership will represent England in Europe, a situation that would change were Worcester Warriors to beat Bath in the final of the European Challenge Cup to take the sixth and last slot. Leicester, the domestic champions, must beat Harlequins at Welford Road if they are both to fend off the Irish and have any hope of competing in the play-offs.

Yesterday was undoubtedly a blow to Wasps who have two more games to play in the space of four days: they travel to Newcastle on Wednesday and close against Leeds Carnegie, who are already relegated. On the face of it, they could not have an easier finish but they will not see it that way, knowing that they must take all ten points on offer to give themselves the chance of a home tie.

“You don't win things in the regular season,” Dallaglio growled after the concession of the double to Gloucester and the first home defeat in the Premiership since Wasps lost to Leicester back in September. “I would rather have lost today than in the play-offs but we will be in the play-offs.

“This is the wake-up call to inspire the players in our squad. We let Gloucester in for some soft scores, I thought, and we got what we deserved. But we're a side that wins when we have to win and we understand the task in hand.” It is for Wasps to show the finishing form that brought them the Premiership title in successive years from 2003 to 2005. They could reach 70 points in their remaining games but the carrot for Gloucester is to beat Bath, two points behind them today, and remain at number one for the play-offs on May 18. “We have a good record in that respect and I would like to maintain it next week,” Dean Ryan, Gloucester's head coach, said.

“But it's more important we get used to winning big games, like this one against Wasps, and the more we do the better we'll get. We still have a lot of growing up to do and we are still coming to terms with how physical the game is at the top end.” It will have done Gloucester no harm that Martin Johnson, England's new manager, was in the capacity crowd at High Wycombe to watch them take this significant step. The game offered potential candidates for next month's tour to New Zealand, in terms of players and leaders given that Mike Tindall, the Gloucester centre, could take over the England captaincy from the injured Phil Vickery while Tom Rees, the Wasps flanker, is one of the younger players in contention.

Sale, the 2006 champions, guaranteed themselves European qualification by beating Harlequins despite being reduced to 13 men at one stage, when Andrew Sheridan and Juan Fernández Lobbe were sent to the sin-bin. “It's never easy to come to a top-four side and win,” Philippe Saint-Andre, their director of rugby, said. “Now we're sure to finish in the top five and if we beat London Irish next week, we will be in the semi-finals.”