Klasnic sealed a 1-0 triumph in the fourth-round replay at the DW Stadium in the 66th minute, collecting Mark Davies' pass and smashing a shot beyond Latics goalkeeper Mike Pollitt.
With Sturridge - who has netted three goals in three games since joining on loan from Chelsea - cup-tied, Klasnic came in as one of six changes made by Coyle and was paired up front with Johan Elmander, as Kevin Davies dropped to the bench.
In the opening 45 minutes Elmander hit the post, while Klasnic failed to make the most of a one-on-one situation and then completely missed the ball when trying to connect with a cross into the box. The Croatian made amends after the break, though, and overall Coyle was pleased with a performance from his front two which he feels demonstrates the competition for places at Bolton in that department.
"I think we all know, he (Klasnic) had a couple of wonderful, gilt-edged chances in the first half and never took them," Coyle said. "But that is the mark of a top striker - that they keep going and are prepared to miss, knowing that the door will fly open and they will score goals.
"He did that and it was great. He was out on his legs at the end of the game, which I expected because of how hard he worked. His chances, as he knows because it has been stop-start with injury, have been limited. But as a manager, what a great problem to have, with the pairing that have played the last few games in the Premier League, Kevin Davies and Daniel Sturridge, not starting and Klasnic and Johan Elmander showing they are top players."