Round 21 of the Aviva Premiership kicks off on Friday evening with the league's basement side entertaining last season's champions.

The Newcastle Falcons host Saracens in front of the ESPN cameras with Gary Gold's men still hopeful of pulling off the most remarkable of escapes. After their impressive 29-20 victory over Gloucester last weekend, Newcastle are within four points of Wasps who are in eleventh. Saracens, meanwhile, kept up their charge to a home semi-final on track with a efficient 28-19 victory over London Irish last Saturday.

Ahead of the clash Gold, who has named an unchanged side from the one that defeated Gloucester, has called on his charges to have a 'cup final' mindset once again.

"In the last few weeks we have been in a situation where every game has been a cup final and this week will be no different," Gold said. "Saracens will be right up for it as they are playing for a home semi-final and we are playing for Premiership survival.

"The type of style of rugby that they play is incredibly difficult to play against and each player knows exactly what they are doing."

Saracens have made two changes to the side which overcame the Exiles ahead of their match with the Falcons. Owen Farrell comes in at fly-half, with Charlie Hodgson dropping to the bench, while James Short replaces Michael Tagicakibau.

On Saturday the day kicks off with Bath hosting the Falcons' relegation rivals Wasps. Wasps were hammered last Saturday by Harlequins while Bath were seen off by Sale. But for Bath the match will hold special significance for Duncan Bell. The 37-year-old is set to hang up his boots at the end of the season and Saturday's match will be the last time he runs out at the Rec for Bath. Bell is named on the bench with rugby league convert Kyle Eastmond joining him. In the first XV, Stephen Donald is recalled to fly-half while Ben Skirving partners Stuart Hooper in the second-row. Lee Mears gets the nod at hooker with the back-row consisting of Simon Taylor, Carl Fearns and Josh Ovens.

For Wasps, ahead of their final match of the season with the Falcons, they are desperately searching for a win. Boss Dai Young has opted to make three changes for the match with Dom Waldouck coming in at inside centre while in the pack Billy Vunipola starts at No.8 with Sam Jones and Jonathan Poff flanking him. Skipper Richard Birkett and Joe Launchbury start in the second-row.

Bath's conquerors Sale travel to Gloucester with the match carrying the intriguing subplot of the whole Bryan Redpath affair. He resigned from his role as Gloucester head coach on Tuesday and while he put the reasons for his exit down to his side's performances, the rumours linking him with the vacant director of rugby position at Sale refuse to go away.

The match could also be instrumental in deciding who gets the elusive sixth place finish in the league with Heineken Cup qualification at stake. Interim boss Carl Hogg has made three changes to the Gloucester side. Tim Molenaar comes in for Eliota Fuimaono-Sapolu in the midfield and Dave Lewis is back at scrum half in place of Nick Runciman. The only change in the pack sees Luke Narraway sidelined with a tight hamstring and he is replaced by Scotland international Alasdair Strokosch.

Sale have also opted to make a few changes with Will Addison coming into the side at outside centre in place of Johnny Leota and Cillian Willis starting at scrum-half. In the back-row Mark Easter gets the nod instead of Richie Vernon.

Elsewhere on Saturday, the Premiership's in form side the Leicester Tigers travel to Harlequins. The Tigers broke the record for the most consecutive bonus point victories with their win in the East Midlands derby last Saturday while Harlequins kept up their charge for the top spot in the league with a convincing win over Wasps. Quins make just one change with former All Blacks fly-half Nick Evans starting at half-back alongside Danny Care.

Leicester have also only made one change from the side that overcame the Saints with Geordan Murphy captaining the side from fullback. Scott Hamilton is relegated to the bench where he is joined by Graham Kitchener.

The final match to complete Saturday's line up comes from Sixways. Richard Hill's Worcester Warriors take on London Irish and while both sides look set for a mid-to-lower table finish, the teams will look to end their season on a high. For the Warriors, Kai Horstmann captains the side from the back-row with Dale Rasmussen his vice-skipper in a week where the club have announced that both will leave at the end of the season. Horstmann is accompanied in a new look back-row by Sam Betty and Jake Abbott. The other change in the pack comes in the front row where Ed Shervington gets a start. Scrum-half Jonny Arr is the final change in a back division that will also see farewell games for wing duo Miles Benjamin and Marcel Garvey - who was announced by Castres as one of their new signings on Friday.

London Irish have made four changes for the match with Steven Shingler starting at fly half, Max Lahiff and Leo Halavatau joining David Paice in the front row and David Sisi coming into the back row.

On Sunday, all eyes will be on Sandy Park. The Exeter Chiefs have been the story of the season and after securing Heineken Cup qualification for the 2012-13 campaign, they stand on the brink of the playoffs. Their opponents, the Northampton Saints, are in the same situation with Jim Mallinder's charges still looking to break into the top four.

The Chiefs fell to the Saints earlier on in the season and coach Rob Baxter has opted to shuffle his pack for the clash. He has recalled Jason Shoemark with the Kiwi starting in the centres. Luke Arscott is the man to make way and Craig Mitchell also comes in for Chris Budgen on the bench. And the Chiefs also face an anxious wait over Pumas winger Gonzalo Camacho who has been cited in the wake of their win over the Warriors for a dangerous tackle.

For the Saints, Stephen Myler gets the nod at fly-half with Mark Sorensen coming in for Samu Manoa in the second-row. Ryan Lamb and Teimana Harrison are included on the bench.