Marchenko has won both their previous matches. Both wins were on indoor hard courts and he took both matches in straight sets. The most recent was in September 2013.
Marchenko had an excellent win over Seppi in the last round. Seppi was more motivated than I had expected following his recent wedding but Marchenko came through in a third set tie break. He was broken just once in 3 sets.
Mahut had a comfortable first round win over wild card Haltys. He saved the only break point that he faced and won it in straight sets.He has been in decent recent form reaching the third round of the US Open.
I think we see at least 1 tie break here and value is on Marchenko to take a set or maybe more. Lay Mahut around 1.30