When was the last successful war China had before 1914?
Well, if you mean against Westerners, a Chinese force led by the Triad kicked the Dutch out of Taiwan in 1662. Later on, the Qing dynasty won a limited war against Russia in 1686 (which led to the signing of the Treaty of Nerchinsk in 1689).
One could argue, though, that the Taiping Rebellion was a civil war in all but name, considering that it had the highest death toll in any war until WW2, and the Qing dynasty did win it, if at a horrendous price.