The Warriors go into the game knowing they can leapfrog the reigning English Champions at the top of Pool 3 with a five-point victory despite having lost the reverse fixture 3-13 in October.
Hastings is the only change to the back-line that started Sunday's 33-24 victory over Cardiff Blues at Scotstoun.
Siua Halanukonuka starts in the front-row with Oli Kebble and Grant Stewart, both having scored tries at Scotstoun on Sunday with the hooker also named Heineken Man of the Match.
Tim Swinson is brought into the second-row with Robert Harley switching to the blind-side flank. Chris Fusaro starts at 7, as captain Ryan Wilson moves to the back of the scrum.
On the bench Adam Ashe, Matt Smith, Huw Jones and Nikola Matawalu are new inclusions in the matchday 23.
Meanwhile, co-captain Callum Gibbins has successfully undergone ankle surgery on an injury sustained in last weekend's victory over Cardiff Blues and faces a minimum recovery period of eight weeks.
Matt Fagerson's shoulder injury sustained in the same game requires further assessment, however early signs suggest the back-rower faces an extended lay-off. More precise return to play timings for the 20-year-old will be provided in due course.
Glasgow Warriors Head Coach Dave Rennie said: "We're going to London with the mentality that we want to top the group and earn ourselves a home quarter-final.
"What we know is we're going to have to take our chances. Saracens are a strong defensive side, so our conversion rate is going to have to be better than it has been in recent weeks to get the victory.
"The opportunity to play knock-out footy is in our own hands and that excites us. We've prepared well and have a side on the park that knows they can win on the road."
15 Stuart Hogg
14 Tommy Seymour
13 Nick Grigg
12 Sam Johnson
11 DTH van der Merwe
10 Adam Hastings
9 Ali Price
1 Oli Kebble
2 Grant Stewart
3 Siua Halanukonuka
4 Tim Swinson
5 Jonny Gray
6 Robert Harley
7 Chris Fusaro
8 Ryan Wilson (Captain)
Substitutes
16 Kevin Bryce
17 Alex Allan
18 D'arcy Rae
19 Adam Ashe
20 Matt Smith
21 George Horne
22 Huw Jones
23 Nikola Matawalu
Players unavailable: Fraser Brown (knee), Matt Fagerson (shoulder), Zander Fagerson (ankle), Bruce Flockhart (ankle), Callum Gibbins (ankle/knee), Peter Horne (knee) and George Turner (ankle)