A system for body tissue ablation, the system comprising: a memory, which is configured to store a value of target amount of ablation energy needed to create a specified lesion in tissue in a body of a patient; an ablation probe, which is configured to make contact with tissue; a generator, which is configured to generate an ablation signal; and a processor, which is configured to; control the generator and the ablation probe to apply the ablation signal to the tissue with the target amount of ablation energy during a smallest time duration permitted within a defined maximum-power constraint; and control the probe, during application of the ablation signal, to: apply irrigation fluid in a vicinity of the tissue; monitor a temperature in the vicinity of the tissue; if the monitored temperature exceeds a defined maximum-temperature limit, increase a flow of the irrigation fluid; and if the monitored temperature exceeds the defined maximum-temperature limit, but the flow of the irrigation fluid exceeds a defined maximum-flow limit, the processor is further configured to control the generator to reduce a power of the ablation signal and extend the time duration of the ablation signal. a memory, which is configured to store a value of target amount of ablation energy needed to create a specified lesion in tissue in a body of a patient; an ablation probe, which is configured to make contact with tissue; a generator, which is configured to generate an ablation signal; and a processor, which is configured to; control the generator and the ablation probe to apply the ablation signal to the tissue with the target amount of ablation energy during a smallest time duration permitted within a defined maximum-power constraint; and control the probe, during application of the ablation signal, to: apply irrigation fluid in a vicinity of the tissue; monitor a temperature in the vicinity of the tissue; if the monitored temperature exceeds a defined maximum-temperature limit, increase a flow of the irrigation fluid; and if the monitored temperature exceeds the defined maximum-temperature limit, but the flow of the irrigation fluid exceeds a defined maximum-flow limit, the processor is further configured to control the generator to reduce a power of the ablation signal and extend the time duration of the ablation signal. control the generator and the ablation probe to apply the ablation signal to the tissue with the target amount of ablation energy during a smallest time duration permitted within a defined maximum-power constraint; and control the probe, during application of the ablation signal, to: apply irrigation fluid in a vicinity of the tissue; monitor a temperature in the vicinity of the tissue; if the monitored temperature exceeds a defined maximum-temperature limit, increase a flow of the irrigation fluid; and if the monitored temperature exceeds the defined maximum-temperature limit, but the flow of the irrigation fluid exceeds a defined maximum-flow limit, the processor is further configured to control the generator to reduce a power of the ablation signal and extend the time duration of the ablation signal. apply irrigation fluid in a vicinity of the tissue; monitor a temperature in the vicinity of the tissue; if the monitored temperature exceeds a defined maximum-temperature limit, increase a flow of the irrigation fluid; and if the monitored temperature exceeds the defined maximum-temperature limit, but the flow of the irrigation fluid exceeds a defined maximum-flow limit, the processor is further configured to control the generator to reduce a power of the ablation signal and extend the time duration of the ablation signal.