Glasgow Warriors (10) 30
Tries: van der Merwe, O'Hare, Evans Cons: Jackson 2, O'Hare Pens: Jackson 3
Edinburgh (12) 18
Pens: Blair 6
Evans (left) scored Glasgow's third and final try
Glasgow Warriors claimed victory over Edinburgh in the first leg of the 1872 Cup at Firhill.
The visitors were in front at the midway point despite DTH van der Merwe's try for Glasgow.
David Blair's precise kicking had given Edinburgh their 12-10 half-time advantage and the fly-half's accuracy continued in the second period.
But Hefin O'Hare's try turned the match in Glasgow's favour and Max Evans also crossed the line for the hosts late on.
The Magners League match survived a morning pitch and safety inspection and began with typical derby intensity as Glasgow looked to retain the trophy they won last season.
The Warriors were penalised for not releasing, giving David Blair the chance to draw first blood for the visitors and the fly-half duly converted.
Blair quickly added a second penalty after another Glasgow infringement.
The home side were dealt an injury blow in the 13th minute when Graeme Morrison was stretchered off to be replaced by Peter Murchie.
But Glasgow slowly worked their way back into the match and were rewarded for their territory when Ruaridh Jackson reduced Glasgow's arrears with a well-struck penalty.
And then, within seconds, the hosts were ahead. Rob Harley retrieved Edinburgh's kick-out, breezed past a couple of tackles and offloaded to the speedy van der Merwe, who raced away to register the game's first try in the left-hand corner.
Jackson added the conversion from an awkward angle but was unsuccessful with his next kick after Edinburgh conceded another penalty.
Murchie was caught offside and Blair brought Edinburgh back to within one point of their opponents with his third penalty and the visitors went in at half-time ahead after another Blair success with the boot.
Blair and Jackson exchanged penalties at the start of the second period before Glasgow's Richie Gray was yellow-carded for kicking the ball away from an offside position, allowing Blair to stretch Edinburgh's lead.
Despite their temporary disadvantage in numbers, Glasgow began to assert themselves, Evans' weaving run and grubber kick through towards Bernardo Stortoni almost creating a try.
When Gray's sin-bin was over, the lock forward was kept on the bench and replaced by Aly Muldowney as Glasgow coach Sean Lineen looked to freshen things up.
Edinburgh's Ross Ford became the second player to be yellow-carded after being penalised for an infringement and Jackson converted the resulting penalty.
And more pressure from Glasgow created the chance for O'Hare to burst through and touch down to put the home side in front again, Jackson adding the extras.
The Warriors continued to make their extra man count in the closing stages and Evans found space to turn inside and cross the line under posts, giving O'Hare a straight-forward conversion.
Glasgow replacement Chris Fusaro and Edinburgh's Scott MacLeod became involved in an angry exchange near the halfway line and both were promptly shown a red card seconds before full-time.
The two sides will meet again in the second leg at Murrayfield on Sunday.
Glasgow: Stortoni, O'Hare, M. Evans, Morrison, van der Merwe, Jackson, Gregor, Welsh, Thomson, Low, Gray, Kellock, Harley, Barclay, Vernon.
Replacements: Aramburu for O'Hare (74), Murchie for Morrison (12), Pyrgos for Gregor (78), Grant for Welsh (58), Hall for Thomson (56), Tkachuk for Low (76), Muldowney for Gray (60). Not Used: Fusaro.
Edinburgh: Thompson, L. Jones, Cairns, Houston, Visser, D. Blair, Laidlaw, Jacobsen, Ford, G. Cross, MacLeod, MacKenzie, Newlands, Grant, Rennie.
Replacements: Kelly for Newlands (66). Not Used: Traynor, Young, A. Turnbull, McInally, King, De Luca, Webster. Att: 7,062
Ref: Andy McPherson