Mercedes boss Toto Wolff says the reigning champions have "no breathing space" as it bids to win a third successive title, and is wary of an increasing threat from rivals Red Bull.
Red Bull claimed victory in Spain courtesy of Max Verstappen after Lewis Hamilton and Nico Rosberg collided, while Daniel Ricciardo was on course to triumph in Monaco until a botched pit stop.
Hamilton went on to secure his first win of 2016 but Wolff is nonetheless adamant that Mercedes cannot afford to slip up as its rivals edge closer to the front of the pack.
"The main thing we took away [from Monaco] was the very real threat from Red Bull," Wolff explained.
"It took a bold strategy, a big push from Lewis and an even bigger slice of luck with Daniel's slow pit stop to get us that win.
"I've said this many times before - but we have no breathing space in this Championship. Maintaining any advantage is a constant battle - and the pressure is only getting bigger."
Wolff added that Mercedes still has the potential to make further gains, and emphasised that improving the reliability of the W07 Hybrid remains a primary concern.
"This unpredictable season has been great for the sport and shows that Formula 1 is alive and well," he commented.
"But, for us as a team, there is clearly work to do. There remains room for improvement in our reliability - but the push for more performance has become increasingly important too."