I don't think it's done using portamento, those sounds. It seems to me that the longer notes rise more in pitch, and also there's some filter following the envelope as well - at the same time - that gives it that slide texture to it... It's a matter of trying, but you'll get pretty close with filter envelope to osc1 pitch on mod matrix. Bare in mind that the timbre needs to get close to, altough it seems like a sawtooth wave, possibly detuned to me... You can work with osc2 detuned, or a combination of both in sync maybe, with osc2 slightly detuned... Also, you can use the unisson for that detuning effect as well. But it's a pretty straightforward kind of sound. And also remember: it's impossible to achieve a particular sound without the complete audio path of it, which doesn't end on the synth itself, of course... So you still have to figure out how to place it in the mix: if it really stands out or not, etc... Good luck, and have fun with your sound designing!