The British duo, whose combined age is 38, put on a near-perfect display in the opening set, not offering their opponents a chance of a break while breaking to-love on two occasions as they raced to a 6-1 success in just 22 minutes.
Watson and Robson broke again in the third game of the second but this time were broken straight back before again breaking to take a 3-2 advantage in the set.
They then had two break-point chances at 4-2 but couldn't take them as the German pair held on before breaking back themselves and taking a 5-4 lead.
The Germans continued the momentum and again broke to take the second and level the match.
Watson and Robson got off to a perfect start in the decider by breaking at the first time of asking but they couldn't take advantage of this break as Lisicki and Kerber hit back straight away.
The Germans' experience shone through in the next couple of games as they first saved two break points on their own serve before again breaking the Brits' serve in the next.
This time Lisicki and Kerber held to take a 5-2 lead and, despite Robson and Watson forcing them to serve it out, they took the decider 6-3.