Mercedes Executive Director Toto Wolff has admitted that the pace Fernando Alonso and Daniel Ricciardo showed at times in Shanghai is something of a concern for the Brackley outfit.
Lewis Hamilton comfortably won the Chinese Grand Prix from pole position, but after making a poor start, his team-mate Nico Rosberg had to battle past Sebastian Vettel, Daniel Ricciardo and Fernando Alonso to finish the race in second place.
Although the German managed to move through the field on the day, Wolff admitted that the pace of both Ricciardo and Alonso was something of a concern.
"In terms of performance the cars were different; Nico lost telemetry before the formation lap, so you are basically blind in the car. The way he managed the situation was really good. In the first stint it wasn't easy for him to overtake the cars; he was following Ricciardo and there was just no way even on the straight to get past him. That shows that you need to get things right and you have to qualify well," he told crash.net.
"Then at the end I think strategy-wise we took the right decisions. We were pushing the second stint quite long because we knew at the end he had to manage the tyres and this is I guess why Alonso had to back off at a certain stage, because he knew he was going to not finish the race on that pace.
"But we have to be cautious; they are coming. You saw Alonso, you saw Ricciardo in the last stint again on similar times to our cars...
"It is quite interesting because what we saw also in the last couple of races is that you have situations in the race on one tyre set when suddenly the times seem to be much more closed up.
"I mentioned Ricciardo's time; he was matching Lewis' time and Nico's time and then in the second stint that wasn't the case, Lewis was going but Nico was struggling behind Ricciardo. So we have to really find out the way our competitors deploy the energy and how the efficiency and the fuel consumption works with them, because it looks like sometimes they go faster and they don't seem to manage that to the end of the race."