Andy Symonds and Cooper Vuna both went over for the hosts, either side of Neil de Kock's try for the league leaders.
Two tries from Ashton and Samuela Vunisa gave the visitors a 29-14 lead at the break.
Ashton and Ben Ransom touched down after half-time before Vuna claimed his second of the match.
As well as playing in the final of European rugby's elite competition against French Top 14 side Racing 92 in Lyon on 14 May, Saracens must now also prepare for a Premiership semi-final against Leicester Tigers.
Worcester, who have finished 10th in the table, are to follow in Sarries' footsteps by moving from playing on grass to an artificial pitch from the start of next season.
Saracens director of rugby Mark McCall:
"We've led the Premiership for three out of the last four seasons. To get 80 points, without our internationals (who were) away for such a long period is a tremendous achievement, but the best is yet to come as we have a young squad.
"Last week we played poorly in the first half against Newcastle but we were impressive today."
Worcester Warriors director of rugby Dean Ryan:
"They are an outstanding side - we struggled with their power and we need to increase depth in our squad if we are going to improve.
"For the 15 minutes before half-time we were nowhere near, we struggled with our kicking game and kept feeding Alex Goode and we never laid a hand on him.
"It's a stark reminder of the top and where we are. We have to bring more power into our squad."
Warriors: Pennell; Heem, Symons, Mills, Vuna; Heathcote, Baldwin; Leleimalefaga, Annett, Schonert, O'Callaghan, Sanderson, Betty, Kirwan, Dowson (capt).
Replacements: Bregvadze, Bower, Johnston, Hewitt, Cox, Mulchrone, Lamb, Grove.
Saracens: Goode; Ashton, Bosch, Tompkins, Wyles; Hodgson (capt), de Kock; Barrington, George, Du Plessis, Kruis, Hamilton, Wray, Brown, Vunisa.
Replacements: Saunders, Lamositele, Figallo, Smith, Fraser, Spencer, Streather, Ransom.
Chris Ashton scored a hat-trick as Saracens prepared for next weekend's European Champions Cup final by comfortably beating Worcester.