"The most pleasing aspect is the manner of the result," Martinez told Sky Sports News. "The performance was as good as it gets away from home.
"We knew if we could replicate our first-half performance in the second that we could win."
The Spanish boss was particularly pleased with the Latics' free-flowing football in open play, although Watson's goal did come from a set piece.
Speaking of the messy winner, Martinez added: "Yes, that's the irony of football. I thought from open play we were a real threat.
"The defending was intense, we showed great concentration and it was a perfect team performance."
A second win on the bounce for Wigan sees them rise to 12th in the Premier League above Liverpool.