The Mestalla outfit are currently on a six-match unbeaten streak in La Liga, with that run of form moving them into eighth and with their sights firmly set on a Europa League position.
"The team is fine, but we must be careful because the form of a team can be fragile. Things are good at the moment because we're winning, but if we aren't at 100% and focused, we could lose and the dynamic changes. We're fine, but we're taking things carefully," he told reporters.
Former Barcelona midfielder Keita moved to Valencia from Dalian Aerbin on a six-month deal in January.