Under normal circumstances an auto Vitz 1.0L cannot outrun a manual Liana 1.3L. Liana creams xli's/gli's even. Certainly not on the higher speed regime of 120+ km.
Could be a number of reasons for this,
1) Gear change timing not done properly. Half the race is about correct gear shifting.
2) Tyres may be too comfy and soft on the Liana. Harder the tyre better the racing performance but poorer ride comfort.
3) Liana takes about 5K km for proper running in for the engine to run in full potential. How much mileage has your Liana made?
4) The Vitz was either modified or was not 1.0L.
Max high-end power output:
Liana 1.3L 66kw/5750rpm
XLI/GLI 1.3L 60kw/6000rpm
City 1.3L 57kw/5800rpm
Vitz 1.0L 53kw/6000rpm
The fact that the Liana is beating the Vitz on pick is what should be expected. So the power to weight ratio is not a factor here. I find it very hard to believe that once Liana is ahead, it's greater power should carry it way beyond the Vitz.
Actually I own an all petrol VXL Cultus. On several occasions I have encountered enthusiastic Vitz drivers over the Super Highway. Once I am able to come near a Vitz at 100 to 120 km range I have usually gone ahead of the auto Vitz in that same 120 to 140 range. It's the pick of Vitz that was too much for my Cultus. But on highways pick doesn't play that much of a role because you don't have that many stops and starts.
The point I am trying to make is that if a Cultus can outrun an auto Vitz on the higher speed regimes then how can a Liana loose after taking a head start?