McGregor, Barry Ferguson, Christian Dailly and Lee McCulloch all returned from injury after missing Scotland's friendly against Croatia in midweek.
Frenchman Jean-Claude Darcheville made his Old Firm debut as the lone striker.
But his striking counterpart Scott McDonald was left on the bench by Celtic manager Gordon Strachan, with Georgios Samaras partnering Jan Vennegoor of Hesselink up front.
Straight from kick-off, Boruc launched a huge punt aimed at the head of Vennegoor of Hesselink as Celtic indicated how they were set to play.
It was a typically frantic, disjointed and mostly aerial battle from the start, with both sides engaging in an extended game of heady tennis.
Vennegoor of Hesselink failed to connect with Aiden McGeady's menacing cross, while McCulloch flashed a header just wide at the other end.
Celtic were enjoying marginally the better of the early possession without posing any real threat until Samaras threaded a neat ball into the path of Brown in the Rangers box.
The midfielder found himself clean through on McGregor.
The outstanding Thomson scored the crucial winning goal
But, as he attempted to shoot, the ball got caught under his feet and the Rangers goalkeeper did well to scramble the ball away.
Brown ghosted in at the Rangers back-post after 32 minutes, latching on to Samaras' weak header, but he was again thwarted by McGregor.
Rangers were dangerous on the counter-attack and created a flurry of chances in the space of the four minutes approaching half-time.
First, Carlos Cuellar had a header cleared off the line then Ferguson's snap-shot from 12 yards was saved by Boruc.
A quick Celtic break saw Brown in space inside the Rangers box, but again his touch let him down and Rangers punished the mistake, countering at speed.
The impressive Thomson gathered the ball on the edge of the Celtic penalty area and ran towards goal.
He prodded the ball through to Jean-Claude Darcheville, who timed his return pass to perfection.
Thomson ran on to it and swept the ball low under Boruc for a classy finish.
The Ibrox side were spraying the ball about with confidence after the break as Celtic struggled to get possession.
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