Los Che have won eight and drawn three of their 11 La Liga matches this season, with a total of 27 points leaving them in second position in the table - just four points off leaders Barcelona.
However, Marcelino has claimed that there is still plenty of room for improvement as Valencia look to build on their impressive form in the opening months.
"I add a 'but' in every game, because I think we always have to improve in some facets. There's realism and constant analysis of what has brought us here in the locker room. There's no euphoria. We know it is difficult to maintain this," AS quotes Marcelino as saying.
"Well, maintaining this is impossible. Not losing any game in 38 is impossible. But let's enjoy the moment, the attitude, the points we have, the constant support that exists between everyone. We won't reflect this week, we'll rest and from next week we'll prepare for Espanyol."
Valencia, who will travel to Espanyol and welcome Barcelona in their next two La Liga matches, last won the Spanish league title in 2004.